• Mammoth Grip Sprinkler Spacers. Mammoth Grip Sprinkler Spacers are used to stabilize and accurately install sprinkler heads.
• Armada Technologies Pro48 Solenoid Activator / Chatterbox and Pro210 Tone Probe. Portable, irrigation system tester. Activates valves, tests solenoids, tests wire continuity, chatters solenoids, and has a tone generator for wire identification.
• Sprinkler Buddy Sprinkler Head Indicator. The Sprinkler Buddy keeps grass from growing next to or over the sprinkler head, thus make the sprinkler location obvious in the lawn.

Key to common controller features in the table below:

• Stations. Maximum number of valve stations. The actual number of stations may be less depending on which model is purchased. In most cases you need one station for each automatic valve.
• Programs. Number of programs available. Each program can have different start times, operation days, and run times for the irrigation valve stations. You need to use different programs for areas with different water requirements. For example a lawn might need to be watered every other day, but drought tolerant shrubs might need watering only once a week or less. Without separate programs they would both be watered on the same days and the shrubs might drown. More programs allows more flexibility resulting in water savings and healthier plants. Most homes need at least 2 programs, one for the lawn and one for the shrubs. Few homes need more than 4 programs.
• Smart Controller. A “Smart Controller” adjusts the watering schedule by itself throughout the year. Smart controllers are quickly becoming mandatory by law in much of the Western and Southern USA. To read more on Smart Controllers see the Smart Controller FAQ. If the controller has Smart features the following key indicates what system is used:
  • H Historical. Adjusts watering based on historical water use records.
  • HS Historical with a sensor. Fine tunes historic data using current condition sensor.
  • OS Off-site data via phone, radio, Internet, etc.
  • WS Weather station. Has it’s own weather station.
  • MS Uses a soil moisture sensor.
• Master Valve Has a control circuit for a master valve and/or pump start switch. An important feature if you use a pump.
• Rain Sensor Has a circuit for attaching a rain sensor. Shuts down if rain detected (typically the sensor itself is not included.)
• Non Volatile Memory is non-volatile, retains data without a battery even in a power failure.
• Delay A delay can be programmed between valve stations to allow time for slow closing valves to close fully. Another important feature if you have a pump, or if you have low water pressure.

This page contains an index and links to reviews of automatic solenoid valves commonly used in landscape sprinkler systems and other irrigation systems.

Electric Anti-Siphon Valves

Electric Angle or Globe Valves

Notes for tables above:

• DW means the valve has special features for use with dirty water (caution–dirty is a relative term, if you can SEE the dirt you better get a good filter rather than a DW valve!!!)
• PR means pressure regulating. (Caution–the outlet pressure for the valve must be set at least 15 PSI lower than the incoming water pressure for most pressure regulating valves to work properly.)
• Valves are plastic unless noted as brass. (Do not assume brass is better, but also do not assume plastic is better!)

Common Valve Options:

Latching Solenoids

Latching solenoid option: Latching solenoids are special solenoids used most often with battery or solar operated irrigation controllers. A latching solenoid will not work with a standard irrigation controller. The latching solenoids work on a toggle principle. Each time they get an electrical pulse from the controller they either open or close. So when they get the first electric pulse they open. The next time they get a pulse they close. This saves electricity which is why battery operated controllers use them. The bad news is if they ever get “out of phase” they open when they should close and visa-versa. So the sprinklers run all day and turn off for 15 minutes each night. Opps…

3-way Solenoid

3-way solenoid option: A full explanation of what a 3-way solenoid is would require an in-depth knowledge of the hydraulic principles that make a valve work, which is a bit too much to try to explain here. So let’s just say that a 3-way solenoid is a more complex solenoid that is less sensitive to dirt or other contaminates in the water. 3-way solenoids are used on many dirty water or anti-contamination valves. Warning- most 3-way solenoids spit out a small amount of water each time the valve is opened, so be prepared for a few tablespoons up to a cup or more of water to come out. If installed indoors you’ll need a drain for the water to go into.

Dirty Water Valve

Dirty water option: An important note on “dirty water” and “anti-contamination” valves. “Dirty water” as used in the irrigation industry means water with small amounts of particulates or algae particles. As a general rule if the water looks dirty, then it is too dirty for any standard irrigation valve, including those labeled as “dirty water” or “anti-contamination” valves. You certainly don’t want to feed water into this valve, or any other manufacturer’s “dirty water” valve, that has sticks or twigs in it! Dirty water valves, such as this one, are commonly used for things like irrigation using secondary treated sewage. These valves contain internal screens to prevent debris from entering the small passages inside the valve. But remember that big stuff can still get lodged in the main passageways of the valve. Really dirty “sludge” water contains so much garbage that the screens become clogged, even if they are “self-cleaning”. The bottom line is that if you are pumping really dirty water, such as dairy sludge, you should talk to the valve manufacturer before using any valve. One more tip; when you call, talk to one of their engineering staff or a “troubleshooter”, not a salesperson! Almost every irrigation equipment manufacturer has troubleshooters that know the capabilities of their equipment better than anyone. These folks will generally give you a straight answer because they are the poor saps who have to go out and check out the problem if the valve doesn’t work!

Pressure Regulating

With this option the valve will regulate the downstream pressure to a desired maximum level. Lets say your irrigation mainline pressure is 100 PSI and you want to operate spray heads on the valve circuit controlled by this valve. At 100 PSI the spray heads would bow apart. With this option the valve can be set so that it will always keep the downstream pressure at 40 PSI or less. Like all pressure regulators the outlet pressure you set must be at least 15 PSI lower than the inlet pressure for the valve. If not, the regulator to work accurately or may not work at all. So if your mainline pressure is 45 PSI and you set the outlet for 40 PSI it won’t work very well. If the pressure at the valve inlet is 45 PSI you would ned to set the outlet pressure at 30 PSI (45-15=30). You could set the pressure lower than 30 PSI if desired, just not higher.

How to Select the Best Rotor-type Sprinkler:

Click here for an in-depth discussion of rotor-type sprinklers and what facts you should consider when selecting one. You should read this before reading the reviews or deciding on a make or model to use.

List of Rotors & Reviews:

Click here for a list of minimum standards for a good rotor.
Click here for a description of the feature codes used in the list below.

Rotor-Type Sprinkler Heads
Features in red are optional. They cost extra and may require a special order from the factory.

*Caution: Part numbers for some models don’t follow in a logical order that clearly identifies the body style. Check the description to assure it is the correct sprinkler head.

Other Products related to Rotor Heads:

• Mammoth Grip Sprinkler Spacers. Mammoth Grip Sprinkler Spacers are used to stabilize and accurately install sprinkler heads.
• Sprinkler Buddy Sprinkler Head Indicator. The Sprinkler Buddy keeps grass from growing next to or over the sprinkler head, thus making the sprinkler location obvious in the lawn.

Minimum standards:

I think any that any rotor sprinkler worth spending money on should have the following features:

• Must pop-up at least 3 inches (stream height above top of case).
• Must not be a discontinued or test-run product (generally that means at least one year on the market).
• Must have positive spring retraction for the riser piston.
• Must have a wiper seal on the riser piston.
• Must have a filter screen.
• Must have a closed-case (drive unit not exposed).
• If installed in a play area it should have a rubber cover (a rubber cover is so cheap and such an obvious safety item, I can’t think of a good excuse why all rotors shouldn’t have one!)

Feature key:

The following abbreviations are used in the reference chart below for various features of the rotor models:

• WS = Wiper seal. A wiper seal around the pop-up riser keeps dirt out of the sprinkler and reduces water waste.
• SR = Spring retraction. A spring pulls the pop-up riser back into the body after irrigation.
• FS = Filter screen. A screen installed inside the sprinkler helps protect the nozzle from debris in the water which might get caught in the nozzle. This is not a substitute for cleaning out the pipe when installing! I’ve found that most of these screens are only partially effective. A lot of stuff still gets though. The junk will not clog the nozzle but on water lubricated rotor drive mechanisms it can jam in the gears.
• CV = Check valve. The check valve keeps water from draining out of the pipes through the sprinkler head when the system stops running. A “must have” feature if your irrigation is installed on a sloped area. In general, if the elevation changes more than a foot within the valve zone, I recommend you use rotors with built-in check valves. Without this feature the water in the pipes will empty out through the lowest sprinkler head every time the valve is closed. This creates puddles and mud around the lowest heads and also cause excessive air discharge the next time the sprinklers are turned on. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra). Most check valves can be easily added as a retrofit item after the sprinkler is installed. You just unscrew the top, pull out the guts, snap in the check valve, then reassemble. No need to dig up the sprinkler. Check valve conversion kits can be difficult to obtain, and may require special ordering. If you even remotely think you may need them, it is best to just buy a model with a check valve already installed.
• NP = Non-potable water markings. Purple-colored markings are available for the sprinkler, generally with the label “Do Not Drink” on them. In most cases this is a replacement cap for the sprinkler, some are snap on covers that snap over the standard cap. Purple is the universal color for identifying a water source that is unsafe for human contact. In many places treated sewage and “gray water” (water from canals or untreated waste water from sinks or showers) are used for irrigation water, thus these warning labels are needed. This item may be optional, that is, you will only get it with the sprinkler if you request it (and probably pay extra).
• VR = Vandal Resistant. Has a feature that makes the sprinkler more vandal resistant. In most cases this is a lock screw that prevents easy disassembly or removal of the sprinkler without a special tool, probably an Allen wrench. Sometimes a metal cap is also part of the package. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra).
• CC = Closed-Case. This means the drive mechanism that operates the sprinkler is not exposed at any time. An exposed drive unit can get stuff caught in it and jam. Bermuda and St. Augustine grass are particularly tough on open-case rotors as the grass grows into the drive mechanism. An example of an open-case rotor is a impact sprinkler head (the type with the arm that splashes into the water stream to move the stream back and forth.) A pop-up impact head is considered open-case because the mechanism is exposed while it is operating and grass easily gets into the cases. (Professional landscape maintenance people often refer to them as “rat traps”.)
• Arc:40-360° = Adjustable Arc. The first number is the minimum arc, the second is the maximum. If the maximum is not 360°, there is a separate non-adjustable full-circle model you must use for full circles.
• Arcs plates: Means that multiple arcs are available, but only at fixed intervals (not adjustable). A set of plates comes with the head, or is purchased separately, and you install the plate for the arc that best fits the shape of the area watered.
• LA = Low Angle Nozzles. Low angle nozzles are available. These are useful in windy areas. The lower angle means a shorter radius, so the heads will need to be installed closer together. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra).
• SS = Stainless Steel Riser. The riser (the part that pops up) has a stainless steel sleeve around it. The stainless steel wears better in sandy soils where the sand can scratch the plastic riser and cause the wiper seal to leak. The stainless steel sleeve may also reduce damage from other sources (like mowers), although I have not found that it really helps that much. Typically the stainless steel sleeve is made from very thin metal. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra).
• SO = Shut Off Valve. A small valve inside the sprinkler allows you to shut off the water to the nozzle in order to change nozzles. This is a big convenience on large sprinkler systems where it would be a pain to go shut off the valve so you can replace a nozzle in a sprinkler head. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra).
• RC = Rubber Cover. The top of the sprinkler has a rubber cover over it to lessen the chance of injuries should someone fall on it. Highly recommended if you have kids. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra).
• Robot. Sometimes called robot sprinklers, these sprinklers direct a stream of water to fall on specific spots. This works something like when you use a hose to water the yard, and you move the no

How to Select the Best Spray-Type Sprinkler:

Click here for an in-depth discussion of spray-type sprinklers and what facts you should consider when selecting one. You should read this before reading the reviews or deciding on a make or model to use.

List of Fixed Spray Type Sprinklers & Reviews:

Click here for a list of minimum standards for a good spray sprinkler.
Click here for a description of the feature codes used in the list below.

Note that many of the sprinkler model series listed include shrub and 2″ pop-up bodies, which do NOT meet my minimum standards.

*Caution: Part numbers for these products don’t appear to follow in a logical pattern that clearly identifies related products. Don’t rely on the part numbers alone!!! Carefully check the descriptions, product labels, and look over the product itself to assure you are getting the correct item.

(NS) means nozzle sold separately.

Other Products related to Spray Heads:

• Mammoth Grip Sprinkler Spacers. Mammoth Grip Sprinkler Spacers are used to stabilize and accurately install sprinkler heads.
• Sprinkler Buddy Sprinkler Head Indicator. The Sprinkler Buddy keeps grass from growing next to or over the sprinkler head, thus it makes the sprinkler location obvious in the lawn.

Minimum standards:

It is my opinion that any spray sprinkler worth spending money on should have the following features:

• Pop-up at least 3 inches (stream height above top of the case).
• Not be a discontinued or test-run product (generally that means at least one year on the market).
• Positive spring retraction for the riser piston. Gravity retraction results in mowed-off nozzles.
• A wiper seal on the riser piston.
• A filter screen.
• Matched precipitation rate nozzles.

Without the above features a sprinkler is not a bargain at any price, maintenance and repairs will cost you more than it would have to just buy a good-quality sprinkler.

Note:

I have not reviewed sprinklers and nozzles separately. It is assumed the sprinkler body will be used with the standard nozzle recommended by the manufacturer. In other words, if you use an ABC brand model ZZZ series body, I assume you will use it with a nozzle supplied by ABC brand for use with their ZZZ series body. The reason I point this out is that the nozzles for many spray-type sprinklers are interchangeable with those made by other manufacturers. They tend to have either “Toro style” nozzles with male threads on the nozzle, or “Rainbird style” nozzles with female threads on the nozzle. In general, I don’t recommend mixing different brands of nozzles and bodies.

Feature key:

The following abbreviations are used in the reference chart below for various features of the spray sprinkler models:

• WS = Wiper seal. A wiper seal around the pop-up riser keeps dirt out of the sprinkler and reduces water waste.
• SR = Spring retraction. A spring pulls the pop-up riser back into the body after irrigation.
• FS = Filter screen. A screen installed inside the sprinkler helps protect the nozzle from debris in the water which might get caught in the nozzle. This is not a substitute for cleaning out the pipe when installing! Most screens are only partially effective.
• RM = Ratchet mechanism. Ratcheting allows the riser to be turned independent of the body. To realign the spray direction you don’t need to turn the entire sprinkler, just the riser. The ratcheting mechanism holds it in the new position. Sometimes called a “friction collar” or “adjustable stem position”.
• MP = Matched precipitation rate nozzles. You can mix various nozzles made by the manufacturer on the same valve zone. For example you could use a 10′ radius quarter circle, 15′ radius full circle, and a 4’x15′ strip spray nozzle all on the same valve zone and the water application uniformity remains constant. Without this feature you get wet and dry areas and lots of wasted water.
• UM = Universal male thread nozzle. This sprinkler uses universal male thread pattern nozzles. That means the nozzle will fit on any brand or model spray sprinkler that also uses universal male nozzles. I strongly recommend that all the spray-type nozzles on a valve zone be made by the same manufacturer. The matched precipitation rates of Brand A nozzles will probably not match those of Brand B.
• UF = Universal female thread nozzle. This sprinkler uses universal female thread pattern nozzles. That means the nozzle will fit on any brand or model spray sprinkler that also uses universal female nozzles. I strongly recommend that all the nozzles on a valve zone be made by the same manufacturer. The matched precipitation rates of Brand A nozzles will probably not match those of Brand B.
• Sediment basin or trap. A sediment basin is a recessed area at the bottom of the sprinkler body where sediment can settle and become trapped. When the sprinkler is turned off, small grains of sand and other particles (sediment) that were caught on the nozzle screen often drop off the screen and settle down to the bottom of the sprinkler. Then the next time the sprinkler is turned on the swirling water rushing through the sprinkler body and riser pushes this sediment back up and eventually it again gets stopped by the nozzle screen. This process repeats each time the sprinkler is run. A settlement basin or trap is a deep recessed area in the bottom of the sprinkler body where this sediment can settle out away from the turbulent flow and it will not be repeatedly blown up into the nozzle screen. This helps the screen stay cleaner and also reduces abrasive wear on the internal parts of the sprinkler that result from sediment repeatedly being swirled up against them.
• CV = Check valve. The check valve keeps water from draining out of the pipes through the sprinkler head when the system stops running. A “must have” feature if your irrigation is installed on a slope or hillside. Without this feature the water in the pipes will drain out every time the valve is closed. This creates puddles or mud pits around the lowest heads where the water drains out. It also causes excessive air discharge the next time the sprinklers are turned on (the sprinklers spit, burp, and cough, which is not good for them or the pipes.) This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra). Most check valves can be easily added as a retrofit item after the sprinkler is installed. You just unscrew the top, pull out the guts, snap in the check valve, then reassemble. No need to dig up the sprinkler. Retrofit check valves can be difficult to find, you may need to special order them from the factory.
• PCD = Pressure Control Discs. These small disks fit into the bottom of the nozzle or are built into the screen. They are essentially a rubber disk with a small hole in it that restricts the water flow. They control the water pressure and flow into the nozzle. They are very handy for reducing the radius of a spray-type sprinkler and they work much, much better than the radius reduction screws on the nozzles. The sprinkler manufacturer will have a chart showing which disc to use with each nozzle to give the exact radius you need. I use PCDs to adjust the radius on all my spray sprinkler systems. If you adjust the radius of a sprinkler using the screw on top of the nozzle, and then the next time you turn it on the sprinkler no longer sprays water, installing a PCD will cure the problem. PCDs are not generic, you must get the specific one made for your brand and model of spray head.
• PR = Pressure regulation. An built-in pressure regulator maintains uniform pattern under varying pressures. These are basically for correcting problems with existing sprinkler systems. Unless installed on a hillside, a well-designed system shouldn’t have pressure variations in it that would require a regulator at the sprinkler. It is generally less expensive to utilize a single pressure regulator at the valve or at the water source. Exception: this pressure regulation feature is helpful when you have sprinklers installed on a steep hillside where the sprinklers at the bottom of the hill will have much more pressure than those at the top. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra).
• SI = Side inlet. An optional side inlet allows the pipe to be installed into either the side or bottom of the sprinkler. This allows the use of a shallower trench. Warning: If you use the side inlet it is very difficult to replace the sprinkler if it breaks! On many brands the pressure regulation and check valve features will not work if you use the side inlet. In general I do not advise using the side inlets. All sprinklers that have a side inlet also have a bottom inlet, so having a side inlet isn’t something to avoid when selecting a sprinkler. It is something to avoid using when you install them! Many 6″ pop-ups and most 12″ pop-ups come with a side inlet whether you want it or not.
• NP = Non-potable water markings. Purple-colored markings are available for the sprinkler, generally with the label “Do Not Drink” on them. In most cases this is a replacement cap for the sprinkler, some are snap on covers that go over the standard cap. Purple is the universal color for identifying a water source that is unsafe for human contact. In many places treated sewage and “gray water” (untreated waste water from sinks or showers) are used for irrigation water, thus these warning labels are needed. This item may be optional, that is, you will only get it with the sprinkler if you request it (and probably pay extra).
• VR = Vandal Resistant. Has a feature that makes the sprinkler more vandal resistant. In most cases this is a lock screw that prevents easy removal of the sprinkler without a special tool, probably an Allen wrench. Sometimes a metal cap is also part of the package. This feature may be optional, that is, it is available but you will only get it with the sprinkler if you request it (and probably pay extra).

Select a Product Review Category:

Product reviews are separated into categories based on the type of product. Click on the type of product you want to research below:

Fixed Spray-Type Sprinklers
Spray-type sprinklers spray a fan of water out of the nozzle, similar to a shower head. They are typically spaced up to 18 feet apart in the sprinkler system.

Rotor-Type Sprinklers
Rotor-type sprinklers have one or more moving streams of water that rotate around the sprinkler head. They are typically spaced from 18 to 45 feet apart. Even larger rotors designed for parks and golf courses are spaced up to 90 feet apart. You need a professional designer for these, even a minor design error will result in huge dry spots!

Valves
Electric solenoid valves used for turning on irrigation circuits (sprinklers or drip emitters.) Includes anti-siphon, angle, and globe type valves.

Controllers
Controllers are fancy timers used to turn on and off automatic valves.

Tools, Accessories, Etc.
Accessories, tools, and other products that don’t fit into one of the above categories.

Common Questions about the Listings & Reviews

Are these reviews biased?

Of course! Expect that any evaluation of any product will be biased by the reviewer’s own personal experiences with the product, observation of installations where the product is used, and/or the experiences related to by others.

Why are there question marks in some of the part numbers?

A question mark character (?) in a part number represents a place holder for ANY letter or number. For example, a product for which I list a part number of 531?? could represent any of the following: 53100, 53190, 531AZ, 531ZA, 531A1, 5319A, etc. Using a variable is simpler than showing many different part numbers that are all essentially the same product with only a minor variation, such as different sizes.

Even more confusion: Sometimes manufacturers repackage their products for specific stores using custom part numbers. Some manufacturer’s use part numbers that make little sense at all (at least no logic that I can figure out!) A number of products are re-branded to carry the name of a different manufacturer, so you will find the exact same product with different brand names on it. All of these practices tend to confuse things. I have tried to include each such item under all the names and part numbers used, however it is just not possible for me to know all of them.

Often a small water supply pipe size between the water company’s big water main in the street and your house results in a low flow to the house. This can add a lot of cost to your new sprinkler system, as a lower flow means you will need more valve circuits. This FAQ explains how much benefit to expect from changing to a larger size house water supply pipe, and how to install the new pipe if you decide it would be beneficial. This FAQ is a sub-page to the City Slicker Water webpage, which is part of the tutorial on how to design a sprinkler system. While written in relationship to irrigation systems, the information here applies to any situation where you want to achieve a greater water flow to the house. It also should be helpful if you just need or want to replace the water supply pipe for the house.

Before you begin any digging call 811. This is a FREE service available everywhere in the USA. “Every digging job requires a call – even small projects like planting trees or shrubs. If you hit an underground utility line while digging, you can harm yourself or those around you, disrupt service to an entire neighborhood and potentially be responsible for fines and repair costs.” See the 811 website for more details. They will come out and mark the locations of all the underground utilities for you. In addition to helping you avoid accidentally digging up a utility pipe or wire, this will also help you locate exactly where your existing water supply pipe is located! Again, both the phone call and the service are free.

Before rushing out to replace the existing water supply pipe with a larger pipe, I suggest that you dig up some of the existing supply pipe and see what size it actually is underground. Often a larger pipe size (probably plastic) is used for the underground portion of the pipe, with a smaller size metal pipe at the end where the pipe comes out of the ground or extends into the basement. If all but 5 feet or so of the supply pipe is a larger pipe size, you probably don’t need to replace it. In this case the larger pipe size you found underground can be used for the “New Replacement Pipe Size” when calculating a new Maximum Available GPM using the table below.

Potential New Maximum Available GPM Values

If you don’t have a water meter, use the shut-off valve size
or smallest existing supply pipe size (whichever is smaller) in place
of the water meter size.

New pipe sizes larger than those shown in the table above do not result in a higher Maximum Available GPM value. However, they may help you by reducing the pressure loss, which can also be beneficial. The Sprinkler Design Tutorial will explain this.

* PE pipe is not recommended. PE has a low burst pressure, and generally PEX pipe is now used in situations where PE was formerly used.

“Maximum Available GPM” is a value used in the Sprinkler System Design Tutorial at IrrigationTutorials.com. It is a measure of the maximum SAFE flow that the house water supply pipe can accommodate. It is possible to force more water through the pipe, however doing so may cause major damage to both the pipe and house’s plumbing system over time. See the tutorial on Water Hammer and Air in Pipes for more information on pipe damage.

The table above is only for use in situations where the water is supplied to multiple households by a water supplier, such as a municipal water system. It is not suitable for use when water is supplied from on-site wells, streams, ponds, etc. For calculating how much water is available using an on-site pump (like with a well) see the Country Bumpkin webpage, for gravity flow sources see the Backwoods Water webpage.

Not all types of pipe listed are legal to use in all locations. Local building authorities regulate through building codes what type of pipe may be used. Codes change and it may no longer be legal to replace the pipe with the same type that was previously used. Local specialized plumbing stores may be able to help you with code compliance, however it has been my experience that advice on codes from larger regional and national outlets is often not correct. I recommend that you contact your local building authorities for advice on what type of pipe to use, often this requires just a simple phone call to them. Many will also offer very valuable tips and suggestions, be sure to also ask how deep the pipe must be buried.

How to replace your water supply line:

In most places a plumbing permit is required to replace the water supply pipe or even to simply cut into it. Contact your local building authorities for details.

Remember that the water supply pipe carries the water you and your family drink! It is important to be careful not to get dirt into it when working. After completion of your work be sure to turn on all your water faucets for several minutes to flush out any dirt or other contaminates. You should sterilize the pipes before using the water from them for drinking. There are products available at plumbing stores for this. Be sure to buy the pipe sterilizer and read the instructions before you start work as you may need to put the sterilizer into the pipes before you reconnect them!

Water mains, Goosenecks, and Corporations Stops

The water company has a large pipe someplace out there that is called the “water main”. It is probably 6 inches or larger in diameter and located in the street or alley. From the water main a smaller pipe goes to your property. This smaller pipe is referred to as a “gooseneck”. At the end of the gooseneck is a shutoff valve called a “corporation stop”. The corporation stop is typically installed near your property line. The idea is that the corporation stop marks the dividing point between you and the water supplier. The pipe coming into the corporation stop belongs to the water supplier. The pipe going out of it typically belongs to the property owner. The corporation stop is usually located in a box or at the bottom of a sleeve with a round plastic or metal cap on it. The cap may only be 4″ in diameter and hard to find. Often it will be covered with dirt or grass, so you will need to poke around to find it, try probing the ground with a pitchfork, metal rake, or screwdriver. Look for a mark engraved into the curb or street pavement indicating the location. The corporation stop will probably be buried below the frost line, so it may be several feet deep in colder areas.

Call 811 and they will come out and mark the location of the water gooseneck for you, and it’s free! This is very helpful in finding the corporation stop since it is someplace on the gooseneck. That will narrow your search area. Sometimes they will even mark the location of the corporation stop. The person who comes out to mark the pipe locations generally has detailed plans that show the exact location of everything. If you happen to be there and are friendly, they are often willing to share lots of useful information with you.

The corporation stop (often abbreviated as “corp stop”) serves as the water company shut-off valve for your house. It is usually operated using a special key or wrench in order to prevent unauthorized use. Fortunately, you can buy a wrench for it at most hardware stores. Get out a flashlight and look at top of the corporation stop first to see what shape the operating nut is, as there are several styles. Also note how deep it is so you can get a wrench with a long enough handle to reach it. Most use a slotted wrench that fits over a raised rectangular shaped bar, like the one in the photo below. If you’re really lucky, it will have a normal handle on it, but don’t bet on it! In some cases you have enough room to operate the corporation stop using a standard pipe wrench. Another trick is to use a basin wrench (a special wrench used to install faucets on sinks) to operate it. You will probably also notice a couple of holes on the corporation stop that align with each other when the valve is in the closed position. These allow the water company to padlock it closed if you don’t pay your water bill! Most corporation stops are hard to turn, so you may need to put some muscle into it. You may be able to get the water company to send someone out to close and open it for you. Often they will do this for free (especially if you ask nice, and you have a good record of paying your water bill on time!)

Photo of an underground water service utility box
containing a corporation stop, water meter, & homeowner shut-off valve.

The photo above is of a particularly nice set-up. Not only is there a corporation stop but there is also a homeowner shut-off valve with an easy to use handle. No need to use a special key, the homeowner can turn off the water themselves without tools in an emergency. I cleaned up the inside of this box before taking the photo. A valve box like this will often have ants, spiders and other disgusting stuff in it so be careful when opening them up. I even found a dead turtle in one once!

Sometimes in cold weather areas there is not a corporation stop located outside. The corporation stop is in your house, usually in the basement, crawl space, or a utility room. In this case you’re pretty much screwed, because the water service pipe is likely owned by the water company and even if it isn’t you can’t easily shut off the water to replace it. Before giving up, call your water company directly (use their local customer service number, not 811) and ask if they have a shut-off someplace between their mainline and your house. Maybe you just couldn’t find it. As a last resort, ask them if they will install a new, larger supply pipe for you. Most of the time they will, but they probably will charge you for doing it. Don’t be surprised if they refer you to a plumbing company to actually do the work.

Add a Second Pipe or Replace the Original Pipe?

How you proceed from here depends on the current layout of your water supply, your budget, and future maintenance concerns. Select the method below that best applies to your needs.

The water meter is installed right next to the corporation stop, or you don’t have a water meter.

• You can simply tap into the existing water supply pipe right after the water meter. Then install a brand new larger size pipe to the sprinkler system. The pipe leading to the irrigation system would be the “new” supply line, using the revised GPM from the table above. The existing supply line to the house would remain unchanged, and the existing flow to the house would remain unchanged. Only the sprinkler system would get the increased flow.
• Tap into the existing supply pipe right after the corporation stop/water meter and install a new second pipe to the house parallel to it. About a foot out from the house connect the new pipe back into the old, smaller pipe leading into the house. That way you don’t need to change any of the pipe in the house walls. This creates two supply pipes side-by-side to the house, with the water going through both of them. The advantage is that this saves some money, as the new pipe can be the same size as the old pipe. The water will go through both of the pipes, so the flow will be much greater than previously (but not doubled, other restrictions still exist, such as the gooseneck and corporation stop.) The downside is that you will now have two separate pipes going to the house. That means twice as much pipe that can break or leak someday. Plus the old pipe will still be there and because it is old, it is more likely to leak or break. Because this method creates future problems, it is not recommended by most professionals.
• Remove the existing water supply pipe between the corporation stop/water meter and the house and replace it completely with a new, larger pipe. About a foot out from the house connect the new pipe to the old, smaller pipe leading into the house. That way you don’t need to change any of the pipe in the house walls. This is the most common method used and is generally the best option.

The water meter is installed more than five feet away from the corporation stop (typically inside the house.)

The options for pipe replacement are essentially the same as those above, however in this case you need to replace the pipe between the corporation stop and the meter. Typically in this situation the meter is inside the house. However, if the meter is someplace out in the yard you will also need to replace the pipe between the meter and the house.

It is much easier if you don’t actually replace the short section of pipe that goes into the house through the wall or floor. Reconnect the new pipe to the old, smaller pipe about a foot outside of the house wall. That leaves a short section of the old pipe going into the house, but is a lot easier than replacing the pipe through the wall or floor. The water will squeeze through the short section and it will work fine as long as there isn’t more than 5 feet of old pipe left between the point you connected the new pipe and the water meter. If there is more than 5′ left, you will need to install new pipe through the wall, or replace the old pipe inside the house once it is through the wall. In other words you leave a short section of the old pipe going into the house through the wall. Once inside it is easier to install a new, larger pipe. You will tap in your new sprinkler system as close as possible after the water meter. Unfortunately, you will have to route the new sprinkler supply pipe out through the wall, which means you will have to drill a hole in the wall. Be sure to seal the hole around the pipe with a good quality flexible water-proof caulking compound! The pipe will move as it expands and contracts, so the caulk needs to remain flexible after it has cured. (Do not use cement for sealing the hole! Standard cement, plaster, and concrete mixes are NOT waterproof!)

Other Items to Consider

Plastic pipe must generally be installed at least 18 inches deep, measured from the top of the pipe to the soil level. All pipe should be installed below the frost line. In some areas that might be 4 feet or more deep. Your local building authorities will have specific requirements on how deep the pipe must be.

How do you connect the new pipe to the old? Most professionals use a compression coupling. If you don’t know what that is, ask at a hardware store. If you make a threaded connection between plastic and metal pipe see the How to Connect Plastic Pipe to Metal Pipe FAQ.

Well, that’s it for this FAQ. Have fun, and remember, safety first when digging and working with trenches. Follow all OSHA requirements. See OSHA’s guide to working around trenches.

What Is Low Head Drainage?

Water that flows onto the sidewalk or curb after the sprinklers turn off, but then stops after a few minutes, is due to a phenomena called “low head drainage”. This occurs when the sprinkler system is installed on a sloped area. The slope does not need to be very high, a change of elevation of less than a foot will often create low head drainage. After the sprinklers are turned off, the water in the pipes drains out through the lowest sprinkler heads and is replaced with air. The easiest way to tell if you have low head drainage is to watch the sprinklers when you turn them on. If they spit and spew lots of air when the valve is turned on, then you have a low head drainage problem. Obviously the water that drains out of the pipes is wasted. The spewing and spitting of air every time you turn on the sprinklers also puts a lot of stress on the pipe and sprinklers.

Leaking Valve or Low Head Drainage?

If you have water flowing from a sprinkler head continuously, even when the sprinkler system is off, then the problem is a leaking control valve. The primary difference between low head drainage and a leaking valve is that low head drainage results in water flowing from the lowest sprinklers for a while after they run, but the drainage stops after the pipes are fully drained. (It may take several hours for the water to drain out of the pipes.) If a valve is leaking the water will run out of the lowest sprinkler head all the time, 24 hours a day, every day. A typical indication that the problem is a leaking control valve is moss or algae growing on the sidewalk due to the constant flow of water. Another common sign is puddles of water around the lowest sprinklers that never dry out. To fix the leaking valve you must disassemble the valve, clean it, replace any bad parts, then reassemble it. See How to Repair a Irrigation Solenoid Valve for instructions. It is possible and common to have problems with both a leaking valve and low head drainage. Fix the valve first, then check for low head drainage.

How to Stop Low Head Drainage:

To fix low head drainage you need to have special anti-drain check valves installed at the sprinkler heads. These check valves prevent the water from draining out of the pipes through the lowest sprinklers. In most cases these check valves are built into the sprinkler head. The anti-drain check valve is an optional feature available when you purchase the sprinkler. This check-valve option is available on all major brands of sprinklers. The anti-drain check-valve closes and holds the water in the pipes when the sprinkler system is off. These built-in check-valves don’t cause any drop in performance of the sprinklers, so they don’t have any impact on your sprinkler system design. Many major brands of sprinklers can be retrofitted with a new internal check valve, although the retrofit kits are hard to find. Most pros simply buy a new head with the check valve feature and replace the old sprinkler with the new one.

You can also buy separate check valves that can be installed on the pipe under existing sprinkler heads. These are a lot harder to install, you need to dig up the sprinkler head, remove it, install the new check valve on the riser pipe, then screw the old sprinkler back into the new check valve. Then comes the hard part- the length of the check valve you just added makes the sprinkler sit about 3 inches higher than it was before! So now you need to lower the sprinkler head. There is also another catch to the retrofit type check-valves; they do result in a drop in the sprinkler’s performance. They typically create a drop in water pressure at the sprinkler inlet of 2 to 5 PSI. In addition to the performance drop the retrofit devices are often more expensive than simply replacing the sprinkler with a model that has a built-in check valve.

Where do you buy sprinklers with check valves or retrofit check valve? Check valves and sprinklers with built-in check valves are often not available at discount stores or big box hardware stores. You will probably need to get them from a local irrigation specialty store or online.

A tentative change to the language of the State of California’s Water Conservation Laws will make the use of low-drainage check valves mandatory for new sprinkler systems starting in the year 2010, and may also require retrofit of many older sprinkler systems with check valves. Expect other States where water conservation is an issue to also implement this requirement.

What is Expansive Soil?

Expansive soils can be found in many areas. Expansive soils expand in size when they get wet, and then shrink as they dry out. As the soil expands and contracts it can create enough force to cause major damage to building foundations, patios, and sidewalks. Expansive soils are also sometimes called shrink-swell soils, swelling soils, adobe, clay, or caliche soils. The damage caused by expansive soil is similar to that of frost heave found in northern regions, but it is NOT the same thing!

Identifying Expansive Soil

Soil that cracks or fractures when it dries is often a sign that it is expansive; however a lack of cracks does not necessarily indicate that the soil is not expansive. Other expansive soils take on a popcorn like appearance when they dry, they look like someone spread little lumps of popcorn shaped dirt on the soil surface. Expansive soils are often clay like, becoming very sticky when wet and hard and brittle when dry. The best way to determine if the soil at a location is expansive is to have an expansion test performed by a soil expert. Expansive soils are common in desert areas, and also in river bottoms or valleys formed by sediment. They typically form in areas that were once covered by seas or lakes. For example, they are commonly found in the deserts of Arizona, the valleys of Colorado, and coastal plains like the Los Angeles Basin and the low lying areas around San Francisco Bay. Often your local government building department can tell you if the soil in your area is known to have expansion problems. Links at the bottom of this page lead to websites with maps of expansive soil areas and more information on expansive soils.

Typical cracking of expansive soil when dry.

Limitations of this Article

Use of this information is at your own risk. Expansive soils vary widely so all I can offer here are broad ideas for ways to deal with it. You will need to decide for yourself the appropriateness of these ideas to your situation. If your soil is extremely expansive you should have a Soils or Geotechnical Engineer advise you on ways to deal with it (they are most often listed under the headings “Engineers – Geotechnical” and/or “Engineers – Soils” in your local phone directory.) Because of the extreme and costly damage that can result from soil expansion, you need to use extreme care in how you deal with it. Please see the Terms of Use for this website.

Water and Expansive Soils

Expansive soils either expand or contract as the amount of water or moisture in them changes. It doesn’t matter if the water is from rainfall or irrigation; the damage is the same either way. In a very simplified explanation, the soil pulls water into it, where the water is stored between the tiny soil particles. Since the water takes up space between the soil particles, the area occupied by the soil expands. The key to controlling damage is to keep the moisture level in the soil next to and under foundations, sidewalks or patios at a uniform level of moisture at all times. If the soil is dry, you want to keep it dry, if it is slightly wet, you want to keep it slightly wet. The amount of moisture in the soil isn’t nearly as important as avoiding changes in the moisture content of the soil.

Concrete Materials

When expansive soils are present it is important to use reinforced concrete to resist the soil movement. This is important because no matter how careful you are, there will be at least some minor soil expansion, and you must be prepared for it. Building and wall foundations should be designed by a qualified engineer. This is not a place to cut corners! Seek out qualified help for the design of foundations. Repair of building damage caused by soil movement can be horrifyingly expensive!

All concrete, including sidewalks and patios, should contain steel reinforcement materials such as rebar and steel mesh. Placing steel in the concrete strengthens it and reduces concrete heaving and cracking. Concrete patios should also have thickened edges with rebar in them to resist soil movement. A local licensed architect, landscape architect, engineer, or concrete contractor can advise you on the necessary thickness of the reinforced edge and the type and quantity of steel mesh and rebar to use. Be sure to discuss with them your budget, and how much cracking and heaving you are willing to accept. Often a compromise is required between cost and having a perfect concrete surface.

The use of concrete pavers or bricks is another option for patios and sidewalks in areas with expansive soils. The pavers are installed without mortar. As the soil expands and contracts the pavers simply move with the soil. The disadvantage of this is that the surface may become very uneven as the pavers move and shift. The advantage is that the pavers generally don’t crack like concrete. Another advantage is that if the pavers become uneven you can remove and reinstall them. Removing and reinstalling them is a lot of work, of course!

Controlling Soil Expansion

The most obvious way to keep expansive soils from expanding is to keep water off of them. Rainwater from roofs should be collected in gutters and then piped away from the building. Drainage should direct water away from buildings. The soil should slope away from buildings for at least 5 feet out from the wall, further is better. While this has nothing to do with irrigation, I mention it because it is important to keep all water away from the building, not just irrigation water. Also keep trees and large shrubs at least 10 feet from buildings as the roots can remove moisture from the soil next to the building and cause it to shrink and collapse.

One way that expansion of soils is controlled by architects and engineers is by mixing lime or other anti-expansion products into the soil. Irrigation water will leach lime and other materials out of the soil, which defeats the purpose of the treatment. Be sure to check to see if the soil under your foundation was treated with lime or a similar anti-expansion material prior to building the structure. If the soil was treated, you need to keep irrigation water away from the treated areas if possible. If possible consult with the building designer as to how far away you need to keep the irrigation from the treated area. If you can’t get a recommendation, keep the irrigation at least 5 feet away. Aprons around the building, as described further below, are a good solution when the soil has been treated.

Another way that engineers deal with expansive soil is to remove the soil and then reinstall it in severely compacted layers (usually with lime added), or just totally replace it with non-expansive soil hauled in from someplace else. This is fairly common in residential building. Normally the soil within 3 to 5 feet of the building foundation will be replaced to a depth of 4 or 5 feet. Be careful not to mix soil from elsewhere around the site with this soil. Also be careful not to mix soil amendments into this area as they will change the non-expansive soil properties. It is best to simply not plant anything within 5 feet of the building foundation. Remember that even if the soil around the building has been replaced or treated, you will still have to deal with expansive soil problems under your driveways, sidewalks and patios.

Finally, architects and engineers may seek to control soil expansion by use of irrigation to help maintain a constant moisture level in the soil. This is a bit tricky because if the irrigation ever fails for any reason, expansion or contraction will occur. This method also requires almost pinpoint accuracy in scheduling irrigation. In the real world this is pretty much impossible to achieve.

Most often some type of compromise solution utilizing several of the above methods of controlling soil expansion is used. In these compromise solutions all water (both from irrigation and rainfall) is kept out of a “no-water zone” that extends at least 3 feet away from the foundation, and often 5 feet. Typically an impermeable apron of some sort is used for this. Then irrigation is used at the edge of this “no-water zone” to maintain a reasonably constant moisture level surrounding it. The following paragraphs look at methods of keeping the “no-water zone” dry and irrigating the edge of the “no-water zone”.

Concrete Aprons

Probably the best method of keeping water away from the building foundations is to use an impermeable apron around the building to keep water away from the foundation. One way this is done is to pour a concrete “apron” all the way around the foundation. The apron needs to extend between 3-5 feet out from the foundation. A plastic moisture barrier sheet is placed under the concrete, because concrete is not water-proof and moisture will seep through it. Also water will flow through the concrete at cracks and expansion joints. It is important that the surface of the concrete apron is sloped so water drains out away from the building and does not pool on the concrete surface. When using a concrete apron you need to understand that the expanding soil will break the concrete apron, and cause it too heave. The only purpose for this concrete is to keep water away from the foundation; it is not intended for use as a sidewalk or patio. It is accepted that soil expansion and contraction due to water seeping under the concrete will result in the concrete becoming uneven and broken! If you want plants up next to the building, put plants in containers on top of the apron. If you want to reduce damage to the concrete apron, add a moisture barrier at the outer edge of it as described below.

Plastic/Rubber Aprons

Another way to keep the perimeter areas dry is to use a plastic or rubber barrier and then cover it with rocks, gravel, bark, or some other loose material. This is often visually more pleasing than the concrete apron above, as the loose material covering the apron does not develop ugly cracks, like concrete. The downside to plastic is that it is not as permanent, yearly checks are needed to make sure the plastic does not have tears or holes in it, and the plastic must be periodically replaced as it will wear out over time. Rubber is more durable but also breaks down over time. The thickest plastic/rubber that can be afforded should be used, thicker material will hold up longer. 20mil thick plastic/rubber is often the minimum thickness used. This plastic/rubber material is often sold for use as pond liners. The plastic/rubber apron must be glued at the top to the edge of the foundation so that water will not enter between the barrier and the foundation. Use high-quality glue or double-stick tape that remains flexible when dry. All joints in the plastic/rubber should be overlapped by at least 8 inches and glued or taped together. The plastic/rubber should not be exposed to any sunlight, as sunlight will make it wear out much faster. Cover the plastic/rubber completely with something to keep sunlight off of it. Generally the covering material is at least 3 inches deep over the plastic/rubber. If you cover the barrier with dirt it is likely weeds will grow and create holes in it, so dirt or soil is not a good choice. It is very important to not let weeds grow on top of the plastic/rubber. If you put potted plants on top of the apron area, check often to make sure roots are not growing out of the pots and down into the barrier!

Typical Apron Detail, click on detail to print.

Moisture Barriers

Moisture barriers are most often used to reduce expansion damage to less important structures like hardscape. (Paved landscape features like driveways, sidewalks, and patios are called hardscape. Hardscape can be made from many materials, such as concrete, bricks, flagstone, etc.) Moisture barriers are also used in areas where the soil is only minimally expansive. A moisture barrier keeps water from seeping sideways under the adjacent hardscape, but does not keep water away from the edges of the hardscape. This reduces lifting of the hardscape surface by the expansive soil. It does not prevent the adjacent soil from moving the hardscape sideways, which is why it is not suitable for areas with highly expandable soil. A moisture barrier is a sheet of thick plastic or metal set vertically along the edge of the hardscape. The moisture barrier typically extends at least 24 inches in depth; often 36″ deep barriers are used. The moisture barrier must be glued at the top to the edge of the hardscape so that water will not enter between the barrier and the hardscape. Use high-quality glue or double-stick tape that remains flexible when dry. Moisture barriers should be checked at least once a year to assure the barrier is still firmly glued to the edge of the hardscape. Moisture barriers need to be continuous with no gaps, cracks, or unglued joints between the sections. Typically the moisture barrier sections are both overlapped and glued or taped together at any joints. It is critical that water not be able to get through or behind the barrier. The moisture barrier needs to be thick enough that roots will not easily grow through it and create holes in it. Often 20mil and thicker plastic is used. If metal is used for the moisture barrier it should not be something that will rust.

Typical Moisture Barrier Detail, click on detail to print.

Using Irrigation to Maintain Uniform Moisture

Often Geotechnical Engineers will recommend that irrigation be used to maintain “uniform soil moisture” levels. The theory is that if the moisture level stays uniform at all times, the soil will neither expand nor contract. This is easier to say than it is to do. While irrigation can maintain the needed water in the soil, it takes a top quality irrigation system to apply the water uniformly and it takes skill in timing the irrigations to keep the amount of water in the soil constant and uniform. If the irrigation system is not maintained and operated very carefully, it can worsen the problem rather than help. Remember that the key is keeping the soil moisture at a constant, uniform level. If you decide to keep the soil stable by keeping it moist, you must always keep it at exactly the same level of moistness. If it is ever allowed to dry out or become over-saturated it may cause damage. Because using irrigation to maintain uniform soil moisture is difficult, it is best to use irrigation only in combination with the use of a apron or moisture barrier as described below.

Maintaining Water Uniformity in the Soil

Water content of irrigated soil varies tremendously. Immediately after irrigation the water content is very high, and then it recedes with time until the next irrigation. This is true of both sprinklers and drip systems, but sprinklers add even greater variability than drip. As the water moves down through the soil and away from the heat of the sun and air circulation, it disperses. As a result the moisture level in the soil tends to stabilize and become relatively uniform. Stable and uniform soil moisture is exactly what is desired for reducing the soil expansion problems. This is the reason that foundations of buildings on expansive soil are often 3 or 4 feet deep, extending down to where the soil moisture levels are more stable. But often a 3-4 foot deep foundation is not practical, or for whatever reason was not utilized. Fortunately, water also moves sideways through the soil, not just down. So we can mimic this “soil depth effect” at the surface to some degree by sealing the surface so that water neither enters it nor evaporates from it. This way the water can move sideways out from our irrigation source, and as with moving down, the moisture level will become more stable and uniform as we move away from the water source. All we need to do is block water from entering or leaving the soil at the surface level. This is the theory behind the use of concrete and plastic aprons described above. An apron 3 to 5 feet wide is placed around the entire building. Irrigation is installed at the outer edge of this apron. This keeps the irrigation well away from the foundation and helps maintain moisture levels more uniform near and under the building or patio. When water from rainfall or irrigation enters the soil, it moves sideways through the soil, by capillary action, under the edge of the apron. By the time it has moved 3-5 feet sideways under the apron, the moisture level is dispersed and reasonably stable and constant.

It is critical that the irrigation system be run at regular intervals to keep the moisture level stable. I strongly suggest the irrigation be automated with a timer and checked regularly. You can also use automatic soil moisture sensors to control the irrigation. There are many available on the market, but my experience has been that they are not fool-proof. You can’t just set them and forget them. The oldest type is called Tensiometers. There are also solid state sensors that require less maintenance than the older style Tensiometers. There are constant arguments in the industry as to which is better; I really don’t have an opinion on this. They are heavily influenced by local conditions, particularly soil type and salt content; you will need to do some research to find the one best for your situation. Many of the soil moisture sensors are designed to keep the moisture from dropping below a given level, but do not guard against too much water in the soil.

Drip Irrigation

It is my opinion that you will get the most uniform moisture applications from a drip system. It is important that the drip system uses evenly spaced emitters, generally around 12 inches apart on the tube. There are a number of products that come with emitters pre-installed on a tube at regular intervals. Or you can buy the emitters and tube separate and install them on the tube yourself at uniform spaces. The drip tubes should not be buried unless you use one of the types that use chemicals to prevent root intrusion into the emitters. The only two I know of are Techline (with Techfilter) by Netafim, and DL-2000 by Toro. The drip tube is typically installed 12″ from the edge of the apron. See the Drip Irrigation Design Guidelines for more help with a drip system design. Remember, uniformity of water application is critical to control expansive soils so proper design is very important.

Soaker Hose

Soaker hoses tend to not give very uniform distribution of moisture, and they have a rather limited life span. They may be appropriate for a short term temporary solution prior to installing a more permanent irrigation system. I wouldn’t consider a soaker hose for a permanent solution. If you do use them, the design and operation is similar to drip systems.

Sprinkler Irrigation

Sprinklers may also be used for irrigation around the apron; however the sprinkler spacing must be head-to-head at the edge where the water application needs to be as uniform as possible. Head-to-head means that one sprinkler sprays all the way to the next. So if the sprinkler radius is 12 feet, they should be placed no more than 12 feet apart. The sprinkler heads should be placed at least 6″ away from the edge of the apron. See the Sprinkler Irrigation Design Tutorial for information on designing a high quality irrigation system. Remember, uniformity of water application is critical to control expansive soils so proper design is very important.

Additional Resources on the Web

Here are some good resources for additional study:
Colorado State University Extension- Horticulture Article on expansive soils by C.R. Wilson, J.G. Davis and N. Mejia for Colorado State University Extension- Horticulture.
Missouri University of Science and Technology A very good article on expansive soils with case studies and solutions for foundations and swimming pools. A must-read article if you plan to build a swi

Wind can really mess up an irrigation system. Even a gentle breeze will blow around the water droplets from most sprinklers. Realistically, a slight breeze from time to time is not usually a problem. But if you expect a steady breeze on a consistent basis, you should take precautions in your irrigation system design. This FAQ will guide you through the possible solutions to wind problems.

If Possible, Avoid Using Sprinklers:

The best way to deal with wind when designing an irrigation system is to avoid using sprinklers. Anytime you spray water into the air there’s going to be problems with the wind blowing the water around. This is simply unavoidable. So the best approach is to avoid irrigation systems that spray water into the air. A drip system is ideal, as the water is dripped directly into the soil from the emitters. Subsurface (underground) drip systems will work for most lawns, however subsurface irrigation is not for everyone. It is generally more expensive than sprinklers and requires different maintenance procedures.

Bubblers are also a good solution, as the water is also applied directly at the soil level. Bubblers work by flooding small areas of the ground with water. Bubblers do not work well for lawn areas, however. The difference between bubblers and drip is in how quickly the water is applied. With a bubbler the water is applied faster than the soil can absorb it, so it spreads out and floods the area. Bubblers are great for shrubs planted in groups on flat soil where the water can spread out. They are not good for slopes where the water will flow downhill and away. Drip systems emit water very slowly and the water soaks directly into the soil without flooding. With a drip system only an area about 3 feet (1m) in diameter around each emitter (or dripper) becomes wet (the size of the area varies with soil type and how much water is applied.) So at least one emitter is required for each plant, for larger plants you might need several emitters. Drip systems work well on slopes. See the Drip Irrigation Design Guidelines for more information.

Re-Design Your Landscape:

Another way to deal with wind problems is through the design of your landscape. In windy areas it is common to design landscapes so that there is no lawn directly adjacent to sidewalks, driveways, roads, buildings, or anything else you don’t want to get wet. A typical lawn for a windy area would be designed to look somewhat like a golf green surrounded by shrubs. (Use a rounded shape for the lawn, like a jelly bean or the meandering edge of a mountain meadow surrounded by forest.) The lawn is then irrigated with sprinklers, and the shrubs are irrigated with bubblers or drip irrigation. The sprinklers are adjusted so that the ones on the upwind side spray slightly backwards into the wind, so that the wind blows the water back onto the lawn. In other words a sprinkler that would normally use a half-circle nozzle on the upwind side might utilize a two-thirds circle nozzle so that it sprays back into the wind slightly. On the downwind side the sprinklers are adjusted just the opposite, with the knowledge that water will be blown slightly down wind. So on the downwind side a sprinkler that would normally have a half-circle nozzle might now use a one-third circle nozzle. Because the lawn is surrounded by shrub areas, any water that blows outside of the lawn area will not be wasted.

Sprinklers and Wind:

The remainder of this article will deal with sprinkler systems and the unique challenges that wind presents when designing a sprinkler system.

Don’t Water When the Wind Is Blowing:

I guess it is obvious, but it is an important factor so here it is: the best way to avoid wind problems is to avoid the wind altogether. Even in the windiest locations there are often times of the day when the wind doesn’t blow as much or as strong. This is typically in the early morning hours. Try to design your sprinkler system so that you can irrigate during these reasonably wind-free hours of the day. This may require you to obtain a larger water source, so that you can irrigate more area in less time. Do a little research to see what time of the day the wind blows the least. In many windy areas the wind dies down a few hours after sunset and doesn’t start up again until shortly after sunrise. Use a fully automatic irrigation system and design it so that it can operate during these reasonably wind-free hours of the day.

Will watering at night cause any harm? Watering at night and during early the morning saves water, as there is less evaporation at these times of day. In humid climates watering at night can lead to mold and mildew problems, however this is not typically a problem in windy areas, as the wind tends to quickly dry out the residual moisture on the leaves. A well-established lawn should not need to be watered more than once a day, even in hot, windy areas. Shrubs need watering even less often. So watering at night, rather than during the day, should not be a problem. In hot, windy areas lawns and other plantings will often look wilted by late afternoon, this is often hard to avoid. Watering during the heat of the day typically does not provide much help with this as the problem isn’t a lack of water in the ground. The problem is that the plant simply can’t pump enough water through it’s roots to stay crisp and fresh looking. A healthier plant with more and better roots is the solution to this problem, and watering too frequently can actually cause less roots to grow. During the establishment period for new plantings (typically the first 90 days) it is necessary to water more frequently, a new lawn often needs water every 2-3 hours on a hot afternoon. When establishing a new lawn it is often necessary to hand water some areas when the wind is blowing in order to assure they get enough water.

Sprinkler Head Selection:

Wind impacts sprinklers when it blows the water away from the place where you wanted the water to be applied. This is called wind drift. Two factors have a large effect on the amount of wind drift. The first is the size of the water droplets the second is the size of the water stream.

Spray-type sprinkler heads: Mist and small water droplets are easily blown by the wind. So it is best to avoid sprinklers that create a lot of mist or very small water droplets. Spray-type heads tend to create lots of mist, especially if there is excessive water pressure at the sprinkler head. This can be addressed simply by properly adjusting the sprinkler to minimize the amount of mist created and not over-spacing the sprinklers. A small screw on the top of most spray head nozzles allows them to be adjusted so that there is a minimal amount of mist created. To avoid over-spacing, if the sprinkler company’s literature says the sprinkler has a 15 foot (4,5m) radius, then do not space them more than 15 feet apart! Remember that for the most efficient operation, most sprinklers require 100% overlap of the area watered by each sprinkler. Yes, I know that seems like a lot of sprinklers, but it is the way it works, so get used to it. Each sprinkler needs to throw water all the way to the next sprinkler. Low angle sprinklers are generally less affected by wind, however you need to use a sprinkler with at least a 4″ pop-up height so that the low-angle spray does not hit the grass.

Rotor type sprinkler heads: Like the spray-type heads they must be spaced so that there is 100% overlap of the watered areas. When using rotor-type sprinklers avoid models that use less than 3 gallons per minute (11.4 l/min) flow. The higher flow rates of larger nozzles result in larger water droplets that are not blown around as easily. Rotors that have multiple streams of water are called stream rotors. Stream rotors can be identified by their appearance when operating, the streams of water look like spider legs rotating around the sprinkler. Stream rotors tend to have very small water streams that are easily moved by the wind. It is probably best to avoid them if you must irrigate when the wind is blowing. The closer the water is to the ground the less likely it is to be blown by wind. So try to avoid sprinklers that have high trajectories. Low angle sprinklers are less affected by wind. The farther the water has to travel through the air, the more likely it is to be blown off-course by wind. Thus in windy areas it is best to use shorter radius sprinklers.

My preference is to base the selection of either rotors or spray-type sprinklers on the size and shape of the area. I generally use rotors in areas where all the dimensions are more than 20 feet (6m). In narrower areas I use spray-type heads. Both sprays and rotors have issues with wind and in my opinion neither provides a clear advantage in windy areas. When dealing with wind, I have found that the type of sprinkler isn’t nearly as critical as proper spacing and adjustment.

For more on sprinkler head spacing see the Sprinkler Spacing Page of the Sprinkler Irrigation System Design Tutorial for the correct method of designing a sprinkler system. Wind makes it critical that you design the system properly; the wind leaves you with no room for error in your sprinkler spacing or pipe sizes.

Valve Zones for Windy Locations:

Design your irrigation system so that the perimeter edges on the up-wind and down-wind sides are controlled by separate valves. Wind problems tend to be the worst along the up-wind edge of the irrigated area. In this area the wind blows the water away from the edge, leaving it dry. The next worst area for wind problems is on the downwind edge, where the wind tends to blow the water out of the irrigated area. Put the sprinklers on both these edges on their own separate valve circuits if possible. This allows you to run those valves during more reliably wind-free times of the day. It also allows you to increase or decrease the watering time in those areas to compensate for the wind problems. If cost or another factor makes it difficult to separate both edges, then try to separate only the up-wind edge to the extent possible. It’s OK to fudge a little and include a few heads that aren’t on the edge on the same valve circuit with the ones on the edge.

Tighten Spacing On the Upwind Edge:

As previously mentioned, wind problems tend to be bad on the upwind edge of the irrigated area. One means of dealing with this is to place the sprinklers closer together on the upwind edge. There is no room for sprinkler spacing errors on the upwind edge. If you’re using spray type sprinklers I suggest a maximum distance between sprinklers of 12 feet. Spray type heads used at 12 foot spacings have water droplets that are considerably larger and less susceptible being blown by the wind. If you are using rotor type sprinklers try to keep the spacing slightly closer than head to head. That means the water from one rotor should spray all away to the next rotor along the upwind edge. Don’t stretch the spacing at all. When in doubt, reduce the space between heads and add another sprinkler head. On the upwind edge it is always better to have more heads than to have less.

Wind Detectors:

To avoid irrigating during times when the wind is blowing you can use a control system that detects wind. One method of doing this is to install a wind speed monitor nearby. It detects high wind speeds and shuts off the irrigation. It does this in a non-smart way; it just shuts off the power to the valves and irrigation stops. This is a really effective method but there is a drawback- the irrigation gets skipped and the landscape may dry up if the wind blows for several days! So if you use a wind detector like this you need to keep an eye on it, wind can make the landscape dry out fast. Some high-end irrigation controllers are smart enough to know that the irrigation was shut down and will attempt to reschedule it at a wind free time. Finally, some irrigation controllers have a remote programming feature where the irrigation schedule is calculated and controlled by a company for you on a subscription basis. In this case the company determines that the wind is blowing in your area based on a wind detector, a nearby weather station, or the weather forecast. When the wind blows hard enough to be a problem they shut off the irrigation and reschedule it for you.

That’s it. These tricks and techniques should help you to have a better irrigation system in windy areas. Remember, the best trick is to avoid the wind by irrigating when it isn’t blowing!

A master valve is an automatic valve, typically an electric solenoid type valve, that is installed at the point where the irrigation system connects to the water supply. The master valve is wired to a special “master valve circuit” on the irrigation controller. (Sometimes this circuit is called a “pump start circuit”. Both types of circuits work similar or identical, and can be used for a pump and/or a master valve.) The irrigation controller turns the master valve on and off. Most, but not all, irrigation controllers have a master valve circuit built in to them.

How a master valve works:

Zone valves are the individual valves that operate a group of sprinklers or drip emitters. A typical irrigation system has several zone valves. Typically one zone valve is turned on at a time, and controls the irrigation in a specific area of the yard. Whenever one of the irrigation zone valves is told to open by the controller, the controller also signals the master valve to open. So the master valve is a little like a back up valve, or a fail-safe valve. The purpose of the master valve is to shut off the water to the irrigation system when none of the zone valves are operating.

Benefits of master valves:

• If a zone valve develops a leak, or doesn’t close, the master valve will act as a back-up to shut off the water. Note that the water will still be on as long as any other zone valves are on. But when all are finished watering, the master valve will shut off the main water supply to the entire irrigation system. While this does not eliminate the water loss or damage, it may minimize it.
• If the mainline pipe (the pipe from the water source to the zone valves) breaks, the water will be turned off at the end of the irrigation cycle and this may minimize water loss and damage. This is especially useful if the mainline is on a hillside, where a leak might cause massive erosion and property damage. Again, the water will still be on as long as any other zone valves are on, so it only will stop the flow when the entire irrigation system is off.
• Some of the more expensive irrigation controllers can use a flow sensor in combination with a master valve to detect leaks and shut off the entire irrigation system. The controller memorizes how much water is used by each valve zone. If the flow sensor shows that the water use is higher than expected, indicating a leak, the controller detects the change in flow and closes the master valve. Unfortunately, most commercial landscape maintenance companies I have dealt with do not know how to use one of these sensor systems, and they disable the sensor. This has happened about 90% of the time on projects I have used these systems on.

Disadvantages of master valves:

• Leaks are more likely to go unnoticed and not get repaired when a master valve is used. This is because most irrigation systems run at night, when nobody is around to see the leak. During the day, when the irrigation system is shut down by the master valve, the leak is not noticed and goes unreported. My experience is that most property owners, homeowners and, yes, even professional landscape maintenance providers, do not regularly check the irrigation systems for proper operation. They make repairs only when damage becomes extreme or someone complains. No, this is not how it should be done, but sadly it is what I see 90% of the time. For this reason a master valve can actually increase the amount of water wasted when a leak develops.
• Master valves lead to premature failure of both PVC and PE (poly) mainlines. This is due to the stretching and contracting of the pipe each time the system is pressurized and then depressurized. This problem is greatly exaggerated at higher water pressures (over 65 PSI or 4,5 bars).
• A master valve can increase the severity of water hammer if the mainline has a pinhole, or one of the zone valves has a slight leak, or if the zone valves close slower than the master valve. This is due to the water draining out of the mainline. When the master valve opens and the pipe refills, the water charges through the empty pipe at a very high velocity, slamming into the tees and ells and causing damage to the pipe system.
• A master valve is one more item that can fail and require maintenance, plus it adds to the initial cost of the irrigation system.

What type of valve should be used for a master valve?

Any electric solenoid valve can be used as a master valve, except for anti-siphon valves. Anti-siphon valves may not be used as master valves. (You should never install an anti-siphon valve in a location where there is another valve downstream of it, if you do it will break the anti-siphon part of the valve.) Many professionals like to use brass valves for master valves due to the higher pressure rating and a general attitude that “if it’s brass it must be better”. I don’t feel that a brass valve is necessary unless you can’t find a plastic valve with a high enough pressure rating. Note that the pressure rating of the valve should be at least double the expected water pressure in the irrigation system. So if you have 75 PSI, or 5,2 bars, of water pressure the valve should be rated for at least 150 PSI, or 10,4 bars. If the master valve is installed before the irrigation system filter, then a “contamination-proof”, “self-filtering”, or “dirty water” valve would be the best type of valve to use as the master valve. These are expensive valves that have a small built-in filter to help protect the valve from dirt, which is a major cause of valve failure. If a valve with a filter is too expensive, a valve featuring a “self-cleaning metering rod” or “self-flushing ports” would be the next best thing. At a minimum the master valve should be equal in quality to the zone control valves. I typically install a filter upstream of the master valve, so most of the time I use the same valve model for the master valve as I use for the zone control valves. If you are designing an irrigation system that uses hydraulically operated zone valves, you will want to use a hydraulic operated master valve rather than an electric solenoid type. Hydraulic operated systems are rare, so if you don’t know what I’m talking about it doesn’t apply to you!

Where to install the master valve:

The master valve can be installed anywhere you would like. It can be before or after the backflow preventer and or the pressure regulator (if used). A few water districts do not allow any valves to be installed before the backflow preventer, but most don’t care. I typically place them in an underground box after the backflow preventer and the pressure regulator. In most cases, putting it after the pressure regulator allows the use of a less expensive valve with a lower pressure rating. In freezing climates the basement, utility room, or a heated shed is a good place for them. If you need to repair the master valve it will spill water when you open it, so make sure it is not installed in a location where a little water spilling out will cause harm. Some master valves spit water out of the valve when they are manually turned on. I suggest that the master valve not be used as the emergency shut off/winterization valve for the irrigation system. Use a separate ball valve installed before the master valve for that. Like all electric valves, sooner or later it will need to be repaired, and you will need to shut off the water while you fix it.

My opinion; when should you use a master valve?

If your mainline is located in a place where a leak might cause severe property damage or a danger to the public, you should use a master valve. If you are willing to pay the price of a flow monitoring irrigation controller with a flow sensor, a master valve can be used as a water conservation measure. The controller should be programmed to shut the master valve only if a leak is detected, and not at the end of every irrigation cycle. For a typical residential irrigation system, and even many commercial systems, I don’t think the benefits of a master valve outweigh the risks or justify the cost. Many water districts in areas with limited water supplies require the use of master valves as a water conservation measure. I absolutely oppose the use of master valves as a water conservation measure when not used with a flow sensor and appropriate irrigation controller. My experience indicates they actually result in an increase in wasted water!

Help, I Need More Water!

How can I get more water out of my existing water supply pipe? How can I increase the minimum available GPM for use in my irrigation design? These questions and variations of them are among the most frequently-asked questions I hear. A typical question would be something like this: “I have a 5/8″ meter and a 3/4″ copper supply, so according to the Sprinkler System Design Tutorial I only have 10 GPM available. This doesn’t seem like very much, so I did a bucket test and got 18 GPM from it! So why can’t I use the 18 GPM figure from my bucket test for my Initial Design Flow?” Well, the answer is you can use that higher value. Of course, you can also jump off a cliff if you want to, but it isn’t a wise choice. There is more involved in determining your Design Flow than just measuring water in a bucket. The good news is that you MAY be able to use a higher flow. The bad news is it isn’t easy or fast to determine if you can! So be patient, and read on. I know this is a long tutorial, but there are a lot of variables and I want to try to give you enough information to make a good decision.

The rest of this FAQ assumes your water is coming to you from a water supplier. If you pump your own water from a well, stream, or pond the only way to increase your water flow is to install a newer and/or larger pump, larger pipe leading to and from it, and possibly drill a deeper well. You will need to see the Irrigation Pumping Systems Tutorial for details on how to do that.

GPM definition: GPM is the standard unit of flow used in the USA, it means “gallons per minute”. This tutorial uses GPM as the flow measurement. Metric countries use liters per minute (l/m) to measure flow. Multiply GPM x 3.78 to get liters per minute.

There are obvious advantages to having a higher flow rate available for your sprinkler system. Increasing your available water supply will reduce the number of valves you need, which could result in a less expensive controller, less wire, and, in general, a lower cost. The best way to increase the amount of water you have available is to have the water supplier install a larger pipe to your property. But in most cases these good options are expensive or not even possible. So the next best solution is to try to force more water through the existing pipe. Unfortunately, there is a lot of really bad advice floating around on how to determine the maximum flow for your sprinkler system. Most sprinkler contractors and sprinkler design guides focus on keeping the short-term costs down. After all, they want to make a sale, and the best way to do that is to have the lowest price. They will save you a few bucks up front when buying your system at the expense of hundreds or even thousands of dollars in repairs later on. The theory is that you are happy you saved money today– and they won’t be around when you are unhappy later! I don’t play that game, so we’re going to look at the risks, and then you can decide if it is worth it.

The Problems with Higher Flows

First, this FAQ assumes you have already worked through the process of calculating your flow used in my Sprinkler System Design Tutorial, and that you want to use a higher flow than what was recommended there. If you haven’t read through at least the first 3 pages of that Tutorial, I recommend you do it before continuing here. The tutorial describes the best way to determine how much flow you will have to work with in designing your sprinkler system.

Keep in mind that what we are discussing here is the maximum available GPM flow. The maximum available flow is the starting point for your design. The actual GPM you should use for your irrigation system may be lower than this value for any number of reasons. As you work through the tutorial above, you will be able to determine the actual GPM you should use.

Now let’s take a look at the significant risks involved in using a higher flow, so you know what you are getting into. The Maximum Available GPM figures I recommend in the Sprinkler System Design Tutorial are set at the maximum safe flow for your pipe size and type, as recommended by the vast majority of experts and the pipe manufacturers.  It is correct that you can get a lot more water through that pipe. No doubt about it. You can force an almost unlimited amount of water through a pipe if you put enough pressure on the water. But is that wise?

Scrubbing

Velocity is the measurement of the speed at which the water is moving through a pipe. In the USA irrigation industry we measure this speed in feet per second (abbreviated feet/second or ft/sec). Flowing water is a funny thing, it seems rather harmless, but at very high velocities bad things begin to occur inside pipes. The first is what is called “scrubbing”. Scrubbing is essentially the wearing away of the inside of the pipe one molecule at a time.  It results from a number of different factors, but it’s easiest just to picture the water as being very slightly abrasive.  It just scrubs away at the pipe.  As the water moves faster and faster, this effect gets considerably worse.  Therefore, most industry sources recommend that you limit flow velocities to less than 7 feet/second, if possible. If the pipe is larger than 2″, the recommended maximum velocity drops to 5 feet/second. Scrubbing is also worse in metal pipes, the slicker surface of plastics reduces the problem. Scrubbing combined with corrosion is the primary reason that copper pipes in houses develop pin holes over time and need to be replaced.

Water Hammer

The second problem that occurs at high velocities is “water hammer”. Remember the Jan & Dean song Dead Man’s Curve?  Let’s say you have a really fast Model A hot rod (what a thrill, can I hitch a ride?) You decide to take it out for a ride on Sunset Blvd. It would be safe to drive at 35 MPH, stupid at 50 MPH and sure death when you hit Dead Man’s Curve at 80 MPH!  In the same way, the water in your pipes can go pretty fast, but what happens when it hits that curve?  How about if it hits a wall? The answer is called “water hammer”.

Water hammer is caused when a valve quickly closes on the fast-flowing water in the pipe. For a great mental image of this, picture a large, very heavy, very long truck full of bananas driving straight into the face of a cliff.  Got the image?  Bananas everywhere!  One last thing to be aware of is that water hammer problems are much more likely if you have water pressure over 60 PSI. If you want to read more on water hammer I have written an entire tutorial on the topic. You can read it here: www.irrigationtutorials.com/waterhammer.htm.

So can you use a higher flow?  Sure, you can.  But all bets are off.   I know it saves a lot of money if you can use a higher flow and have a few less valves.  But if you get a good case of water hammer, you can bet you are going to regret it.  When a sprinkler valve shuts off at 4 AM in the morning and it sounds like the house was just hit by a truck, your spouse may hit you!  Or maybe you’ll just ignore the noise until the morning one of the hoses under a sink blows off due to the pressure surge, and the house is flooded.  Then you may just wish you had spent a little more money on your sprinkler system! Scrubbing, on the other hand, is pretty easy to predict. If you exceed the recommended flows in the tutorial, you are going to get scrubbing damage, especially if you have copper pipe. What is next to impossible to predict is how much damage will be caused. As you increase the flow, the scrubbing gets progressively worse. It also depends on the type of pipe you have and how well it was assembled back when they built your house. If, in general, you have noted that your house is poorly constructed, you might want to think long and hard about this! But if the scrubbing isn’t major, and the pipe and workmanship are good quality, it takes years and years for it to become a problem. How many years varies widely, but more than 10 years seems to be a reasonable expectation.

Well, at this point you need to decide how much risk you want to assume to save a few dollars. Unfortunately, I can’t help you with this. It has to be your decision. So below I’ll give you some new maximum flow rates, and also explain how to do a water hammer test.

Ready to Proceed?

OK, you understand the risks and you want to proceed anyway. The Maximum Design Flows that I give in the Sprinkler System Design Tutorial are based on maintaining a flow below 7 feet/second. Some people in the industry say you can go up to 10 feet per second, especially with smaller pipe sizes. I have never heard anyone with any training recommend a flow higher than that. The maximum flow values in the table below are based on 10 feet/second velocity.  Flows over this value pretty much guarantee you will see major damage in the pipe.

Remember that the maximum flow must be based on the most restrictive pipe that the water passes through on the way to your sprinkler system. For example, let’s say your house has a 1″ PVC pipe that brings the water from the water company mainline out in the street to your house. When the pipe reaches the house, it changes to 3/4″ PEX pipe through the house. In this case if you tapped into the 1″ PVC pipe, then the 1″ PVC pipe would determine the maximum flow. This is because the water going to the sprinklers goes directly from the 1″ PVC pipe into the sprinkler system. You wouldn’t need to consider the 3/4″ PEX because the water never passed through it. However, if you tapped into the water supply inside the house after the pipe becomes 3/4″ PEX, then the PEX pipe would determine the maximum flow because the PEX pipe has a lower maximum flow than the PVC. The most restrictive pipe that the water actually passes through determines the maximum flow.

“What if the smallest pipe is really short? Won’t the water just squeeze through without problems? After all, a lot of water squeezes through a valve, and the opening in a valve is pretty small, right?” Yes, that is correct, and you can squeeze the water through. The problem is the scrubbing. A valve is made with a heavy body so it can stand up to the wear, but pipe, particularly copper, is not. My advice is to replace the small pipe section with a larger pipe. But yes, you can squeeze the water through if it is less than 3 feet long and you accept that the pipe will wear out faster.

NEVER EXCEED THESE FLOWS!
(GPM at 10 feet/second)

Notes on using the table above:

CTS means “Copper Tube Size”, IPS means “Iron Pipe Size”. SDR means Standard Dimension Ratio (the ratio of the pipe wall thickness in relation to the diameter of the pipe).

If your pipe is larger than 1″, you should have plenty of water, stick with the flows in the tutorial! Larger pipe sizes are much less forgiving of high-velocity flows.

What type of plastic pipe is it? PEX and PE are both polyethylene products. There is a lot of confusion over these two products. True PEX is a stronger form of cross-linked polyethylene that has become popular with plumbers in recent years. Both PEX and PE are flexible, and both have a glossy appearance and slick surface. So how do you tell which one you have? Older PE is almost always black, and in most cases PEX is not black. The surest thing to look for are the letters “PEX” printed on the tubing. Making things even worse, white PEX looks a lot like PVC, especially if it is old or dirty! PEX is easily scratched with a fingernail, PVC scratches, but not easily. PEX was not invented until the ’70s, and it is seldom found in homes built before 1975. (It wasn’t officially sold in the USA until 1985. Of course, if your house has been remodeled, you could still have it in a older house.)

PEX tubing. Don’t confuse it with PE or PVC!
Note the labels “PEX” & “SDR-9”.

PVC plastic pipe is almost always white or gray and is more rigid than either PEX or PE. Another type of PVC called CPVC is sometimes used inside homes and often is found in older mobile homes. It is similar to regular PVC, but will be labeled “CPVC” and most often is a yellowish, gold, or tan color. CPVC in homes is usually copper tube size (look for “SDR-11” printed on the pipe), but is also sometimes IPS (SCH 40). Confused yet? Your best bet is to find lettering on the pipe that says what type it is.

CRITICAL! Your maximum flow MUST be based on the most restrictive pipe size and type between the water company’s mainline and your sprinkler system. Even if you use a 1″ PVC pipe for your irrigation system, if you are tapping into a 3/4″ copper pipe to get the water, then the 3/4″ pipe determines the maximum flow. Think of it this way- you may have a huge mouth, but if you are trying to suck soda through one of those tiny straws used to stir coffee you will not get much soda! The pipes leading to your irrigation system are like that tiny straw. The smallest, most restrictive one determines how much water gets through.

Water Hammer Test:

If you’re going to try using a higher flow, you need to perform a water hammer test. I know this takes time and effort, but it is necessary.

This test is absolutely critical if you plan to tap into a pipe that comes out of the side of your house, like a hose bib. This is because you don’t know what size pipes they used inside the walls of your house. Just because the plumber should have used a big pipe doesn’t mean he did. Maybe he ran out of the correct size of pipe and didn’t want to make another trip back to the shop to get pipe, so a small pipe he has handy gets installed. Who knows. All I know is it happens.

Understand that no test is perfect. This test will identify if water hammer will occur under the conditions which you run the test. Conditions can and do change. If you happen to run the test while your water company’s water pressure is abnormally low, you could get a false negative for water hammer. Plus other things can cause water hammer, such as designing your sprinkler system wrong. I do not guarantee that a negative result with this test will mean no water hammer will occur in your sprinkler system.

Tip: If you aren’t familiar with the terms used here, see the Glossary and the Understanding Fittings pages. Also, a picture is worth a thousand words, so here’s a diagram of what I am about to try to explain!

1. Go shopping! Here’s a few of the items you will need:
   • Pressure gauge 0-100 PSI (or higher.)
   • 1″ electric irrigation valve (make sure it has a flow control on it, and it is best if it is the same brand and model you plan to use for your irrigation system.)
   • 1″ brass ball valve.
   • 3 nine-volt batteries.
   • 1″ pipe (more on what type and how much pipe is discussed later)
   • Whatever fittings you need to connect it all to the house water main as described and shown in the diagram above.
   Read all of these instructions, think it through, and make a list before you go shopping to avoid a second trip to the store. You should be able to find all of these items at an irrigation supply store or the plumbing and irrigation sections of most home improvement centers. Tip: lay out all the parts on the floor of the store to be sure you have everything you need and that all the parts will fit together.
2. Tap into the water supply pipe at the point where you want to take your irrigation system water from (the “Water Source Point of Connection” in the diagram above.) You will reuse this tap for your irrigation system water supply, so it won’t be wasted. Keep in mind that the further this tap is from where the water supply pipe enters your property, the more chance you have of creating water hammer problems! The worst possible place to tap into is a hose bib sticking out of the side of the house. The best place to tap into is the supply pipe right after the water meter (if you have one.) The second best place to tap into is right after the main water shut-off valve for your house’s water supply.
3. Install the ball valve as close as you can to the tap point, but make sure it is in a easily-accessible location. This will become your emergency/winter shut-off for the irrigation system, so it will be permanent. You won’t remove it after the test, so do a good job of installing it!
4. Install a 1″ section of pipe going from the ball valve to the pressure gauge location. Suggestion: it will be easier if the pressure gauge and electric irrigation valve are above ground. This pipe can be as long as you like, but should not be less than 12″ long. It can have as many directional changes as needed to get it above ground or outside of the house. If part of this pipe will be inside your basement or crawl space, it should be the same type of pipe that is used inside the rest of your house. In may places it is not legal to use PVC or PE pipe inside or under a house. Even if it is legal I don’t recommend it.
5. Install a tee (a fitting, shaped like a “T”, that adds an outlet to a pipe) and attach the pressure gauge to the outlet of the tee. Most pressure gauges come with a hose adapter on them, which has 3/4″ female hose threads. Most pipe has IPS threads, which are not the same as hose threads. However, you can attach the 3/4″ hose connection onto a 3/4″ plastic male pipe thread with a little force (ie; use a wrench.) This is only temporary, so it will be OK. Do not leave the pressure gauge permanently connected. Remove it after you are done with your test. All but the most expensive pressure gauges will “stretch” over time and stop working accurately if you leave them connected to a water source.
6. Install another short section of pipe after the pressure gauge and then install the electric valve. Note that water may spill from the valve during the test, so it is best if the valve is installed outside.
7. Now install as much 1″ pipe as needed to go from the electric valve to some place where you can dump a lot of water and not make too big of a mess. We’ll call this the “blow off” pipe. This pipe is temporary, so just lay the pipe on top of the ground. This pipe can be up to 100 feet long, if needed. Remember you will need to get a 5 gallon bucket under the pipe outlet, so you may need a few ells in the pipe to go up over the top of the bucket. If you used PVC pipe, let the glue dry for an hour before proceeding.
8. Now slowly open the ball valve to the full-open position. Check the pressure reading on the pressure gauge and write it down. This reading is your static water pressure. You will use it when you design the sprinkler system. If you use my Irrigation Design Tutorial, this will be your “Design Pressure”
9. Now test and break-in the electric valve. Close the flow control on the valve. Next, manually open the electric valve using the on/off lever on the valve (on some valves you do this by turning a knob or loosening a bleed screw, see your valve instructions). Wait 30 seconds, then open the flow control to the fully-open position. The water should start flowing as you open it. Let it run for at least a minute, then turn the manual on/off lever to the off position. It may take up to two minutes for the water to stop flowing through the valve. Don’t panic, this is normal. If the electric valve still does not close after a couple of minutes, it probably has an air bubble caught in it. Again, this is very common with brand new valves. Try re-closing the flow control on the valve, then reopen it. If this doesn’t work, another trick is to go press your hand over the outlet of the pipe to create some back pressure on the valve. (You will get wet doing this!) Once you have it working, break in the valve by opening and closing it a few times, using the manual on/off lever.
10. Now the flow test! Open the electric valve using a test battery setup (see below.) To do this just touch the wires from the valve to the end terminals of the test battery chain. With the wires connected to the batteries the valve should open. When disconnected, the valve should close (again, it may take a couple of minutes to close).  Open and close the electric valve several times to break in the solenoid.
11. Next, open the electric valve using the batteries. Check the pressure gauge. If it shows less than 35 PSI, then slowly close the flow control knob/handle on the electric valve until the pressure on the gauge moves up to 35 PSI. Once the gauge is reading 35 PSI (or more) go measure the flow coming out of the end of the pipe using your bucket (see method below.) If the flow is higher than the maximum flow you determined using the table above, close the flow control knob/handle a little and retest. Continue closing the flow control knob/handle until you get the flow down to (or below) the maximum flow.
12. Finally– it’s time to test for water hammer! Close the electric valve by disconnecting the battery. Did you hear a bump, bang, or multiple bumps when the valve actually closed? If so, that is water hammer. A soft thump heard at the valve is OK. All valves make some sound when they close. What you don’t want is a very solid-sounding thump, multiple bumps, or any loud noise that you can hear in the house. Anything that sounds like a hammer hitting the pipe is bad. Now that you have it all set up, run the test several times late at night when it is quiet and again very early in the morning during the most likely time you will be irrigating.  Do you hear any water hammer at those times?  Listen both at the valve and inside your house.  If you do hear water hammer, you need to reduce the flow a little , (close the flow control knob/handle a little more) then repeat the test. Continue until you reach a flow where you don’t hear any water hammer. This flow is the maximum flow you should use for designing your irrigation system.

Bucket Method GPM flow test:

Get a 5-gallon bucket. Old paint buckets work great. Since most 5-gallon buckets actually hold more than 5 gallons of water, you will need to calibrate the bucket as follows: Find an accurate measuring container, and measure out 5 gallons of water into your bucket. Then mark the water level on the side of the bucket with a marking pen so you can easily see it.  The test is simple. Put the bucket under your water outlet pipe and time how long it takes to fill the bucket to 5 gallons.  The formula for calculating the flow in GPM is: 300 divided by the seconds it takes to fill a 5 gallon bucket = GPM.

Guys- don’t use your wife’s favorite kitchen measuring cup!

Battery test setup:

Use 3 standard 9-volt batteries (the rectangular type with snap connectors on top.) Using the male and female snaps on top of the batteries, snap all three of them together in a chain. This creates a home-made, portable, 27-volt valve tester. Now touch the valve solenoid wires to the end terminals on your battery chain. The valve should open. Easy. Cheap. And it works great!

Using a chain of 9 volt batteries to open a valve.

“Smart Controllers” are controllers that automatically update the watering schedule to allow for changes in water needs throughout the year. So a smart controller will automatically reduce the watering times as the weather gets cooler and less water is needed. Then as the weather begins to warm up, the controller will add more watering time. The way this typically works is that you set the controller for a default maximum watering time, based on the hottest time of year. Then the controller reduces that time amount by a percentage value when less water is needed. There are several methods used by different controllers to determine how much to reduce the watering time. Some controllers may allow for use of more than one method. Here’s a list of the common methods used by smart controllers to determine the watering time:

• Historical. Uses historical weather and water use data for your area to determine what amount of water is required. Typically it only resets the time monthly. While the historic data is not perfect, it still gives significant water savings for most users. You will periodically need to manually override the automatic controller settings, especially if you have unusually hot weather for the month. To setup the controller on some models you simply enter your zip code and it accesses the historic data from it’s memory. On others you have to initially key in the historic data from the user’s manual or a website. Due to the lower cost of this type of smart controller, often it will give you the best financial return on your investment. This is especially true for a small residential irrigation system.
• Historical with a sensor. Uses historical data to determine an initial reduction in watering time, but then further adjusts the time based on a sensor. Typically a temperature sensor is used. If the daily high temperature is higher than the historical data says is normal, it adds more time, if the temperature is lower, it reduces the watering time. This gives more accuracy that the historic data alone will.
• Off-site data. Uses water and/or weather data provided by a remote provider. The controller uses a radio, Internet, or phone connection to obtain the data from either a central data provider, or from a local weather station. Generally there is a subscription charge for the data service and there may also be charges for the telephone, Internet, or radio link. Accuracy is dependent on where the data is obtained from (garbage in, garbage out). If the data comes from a nearby weather station it can be very accurate. If it comes from a central data base of historic data that is expertly manipulated for current conditions it can be very accurate also. So with this type of smart controller you need to ask the provider exactly where the data would come from for a controller installed at your location.
• Weather station. This controller has it’s own weather station that you install with it. It uses real-time data from the weather station to adjust the watering times. It is very accurate if it uses a good weather station.
• Moisture Sensor. A moisture sensor (often more than one) is placed under the irrigation system to measure the actual amount of moisture in the soil. The irrigation time is based on the amount of moisture present. I’m going to get flamed for this, but I wouldn’t be honest if I didn’t tell you that moisture sensors have not been well-accepted by professional turf managers. This is at least in part due to a lack of long-term reliability of the sensor units. There are several types of sensors available. Some require regular maintenance, others do not. There are advantages and disadvantages to each type of sensor. Do some research, as different types of sensors work better with some types of soils than they do with others. Be prepared to spend some time calibrating the sensors and making adjustments. With that said, this is a very accurate method of determining watering times.

Some companies sell add-on equipment, such as moisture sensors, that can be used with any brand of controller to make it “smart”.

With all smart controllers there is an initial shake down period of a few months when the controller will need weekly adjustments. During this time you fine-tune the controller to your actual conditions. After that the controller takes care of the adjustments.

In order to make good decisions about which sprinkler products will work best for you it is necessary to have some basic knowledge of how sprinklers work and what the various options available to you are. Therefore the following is intended to give you the background necessary to understand the terminology used in my reviews.

Sprinklers fall into one of two types based on the method they use to apply water to the ground; spray-type (sprays) or rotor-type (rotors.) Spray-type sprinklers are the type of sprinkler that spray a fixed water pattern similar to how a shower head works. Rotor-type sprinklers use a rotating stream (or multiple streams) of water to apply the water to the ground. Spray-type sprinklers (also called “spray heads” and “sprays”) are typically used for smaller areas. Rotor-type sprinklers (most often simply called “rotors”) are used for larger areas (generally more than 18′ in width.)

Rotor-Type Sprinkler Basics

Rotor is the term used to describe the various sprinklers which operate by rotating streams of water over the landscape. The example which most people are familiar with is the “impact” rotor sprinkler (often improperly called a “rainbird”, Rainbird is the actually the trade name of a sprinkler manufacturer.) The impact sprinkler is mounted on a bearing that allows the entire sprinkler body to spin in circles. It is rotated by the impact of a swinging arm which repeatedly strikes the body of the sprinkler, causing it to rotate slightly each time. You probably know the impact sprinkler best for the distinct sound it makes when operating– tooka, tooka, tooka, tic, tic, tic, tic, tic, tooka, tooka, tooka, etc… You may run into rotor-type sprinklers called “cam drives” or “ball drives”. These are also impact sprinklers, however the impact is caused by either a cam or a ball bearing inside the body of the sprinkler. With ball and cam drive rotors only the nozzle moves. Most of these ball and cam drive sprinklers are no longer sold, but a few, like the Rainbird R-50 (they don’t call it a ball drive, but it is) are still available. While impacts do an acceptable job of irrigating, the jerky motion of the impact drive tends to make them rotate in a less than uniform manner. Thus the impact rotors have now been almost completely replaced by gear-driven rotors, which are very quiet, rotate smoothly, are lower maintenance, and much smaller in size. As with cam and ball drives, only the nozzle on a gear-drive moves. The water moving through the sprinkler spins a turbine, this turns a set of gears, which turn the nozzle. These gear-drive rotors have one or more streams of water which rotate silently across the landscape. The prettiest of these are the multi-stream rotors (or “stream-rotor”) where multiple streams of water rotate over the landscape one after the other. Multi-stream rotors are fascinating to watch but tend to be higher maintenance than the other types of gear-drive sprinkler heads.

Most rotors now come with a set of nozzles rather than a single nozzle. Often these nozzles come attached to what is called a nozzle tree. Just remove the nozzle you want from the tree and install it in the rotor. Save the rest of the nozzles, you may need them later. Multiple nozzles are a big advantage, as you can change to a different size nozzle if needed to help balance your system. Say you have a dry spot between rotors. You might be able to green it up by installing a larger nozzle in the rotors surrounding the dry spot. Some rotors, however, still come with a single, pre-installed nozzle, and some come with stripped down nozzle trees (with only a few of the available nozzle sizes on them.) If you want the whole set of nozzles with these less expensive models, you must purchase them separately. A preinstalled nozzle or limited nozzle tree is common with many of the prepackaged rotors sold at discount stores.

I need to mention a new type of sprinkler, which I am classifying as a rotor since it utilizes a moving stream of water. However, it operates a little different from a traditional rotor. Sometimes called robot sprinklers, these sprinklers direct a stream of water to fall on specific spots. This works something like when you use a hose to water the yard, and you move the nozzle of the hose around to make the stream of water fall on different spots. The size and shape of the area to be watered is programmed into a computer, the computer then controls the sprinklers, telling them where to move the stream and how much water to apply in each spot. Typically they use an electric motor to move the nozzle.

What situations work best with rotor-type sprinkler heads?

Typically rotors are used for sprinkler spacings from 18 feet to 55 feet apart. There are rotors available that can be spaced closer than 18 feet but they are generally not cost effective, as a spray sprinkler will work well at this spacing and cost less. There are also rotors available for spacings farther apart than 55 feet but they are typically only used for golf courses. Most rotors require a lot more water pressure to operate than spray-type sprinkler heads. When selecting a rotor keep Stryker’s Rule in mind; “the water pressure at the rotor head (in PSI) must exceed the distance (in feet) between the heads.”) Thus if you want to space rotors 35 feet apart you will need 35 PSI of pressure at the rotor. (Caution: you will actually need more pressure than 35 PSI to run the system due to pressure loss in the pipes and valves between the water source and the sprinkler. Figure a minimum of 15 PSI more will be required for the pipes and valves.) The small rotors sold for residential use work best at 25 to 35 foot spacings, although with careful design some models can be spaced up to 50 feet apart. As a general rule you should hire a professional designer if you need sprinkler spacings greater than 45 feet. Designing with larger sprinklers requires specialized knowledge as many unique factors must be considered in the design process.

How a Typical Gear-Drive Rotor Works

Water enters the base of the sprinkler. From there it passes through a filter screen and then through a turbine. The water turns the turbine, which powers a set of gears, which rotate the sprinkler nozzle. The water then passes up through the body and exits through the nozzle. Generally the nozzles can be removed and there are numerous nozzle sizes available. At the nozzle there is a radius reduction screw. With most rotors this screw also doubles as the set screw that holds the nozzle in place.

Reducing the Radius and Dealing with Coverage Problems

As the radius reduction screw is turned clockwise the end of the screw comes into contact with the stream of water exiting the nozzle. This distorts the water stream and results in a reduction of the radius. Many people in the irrigation industry refer to this screw as the “break-up screw” because it “breaks up” the water stream. There is a temptation to play around with this screw setting in an attempt to create a better water pattern. However, most modern rotor-type sprinklers are designed to give optimum uniformity with the radius reduction screw not in contact with the water stream. Therefore you should only turn the screw so that it contacts the water stream if you need to reduce the sprinkler radius. Be warned- most people look at the stream of water exiting the nozzle and feel it is not giving a uniform pattern. So they mess with the radius reduction screw trying to get a “better pattern”. Unfortunately, this most often hurts rather than helps. The fact is that without training the average person can’t tell when the water pattern is best by simply looking at it. The moral is if you don’t need to reduce the radius of the stream, then leave the screw in a position where it does not contact the water stream! With that said, there is a situation where the screw does need to be used to break up the water stream to improve the pattern. It occurs when the water pressure (PSI) at the rotor is below the optimum level (indicating in most cases that the system wasn’t designed correctly). You can’t tell if this is a problem by looking at the stream, so look at the ground around the sprinkler. If you have a low pressure problem the sprinkler will create a donut-shaped water pattern on the ground. There will be a very small green area right around the sprinkler head where water leaks from the head. Then there is a dry area for several feet (the donut hole), with a wet area farther out. This creates a pattern on grass shaped like a huge green donut, with a small bit of green in the very center. If this is happening you will need to use the radius adjustment screw to break up the stream so that more water falls closer to the rotor. If there are dry patches located midway between two rotors, but no donut pattern, that usually means the rotors are spaced too far apart, or the radius adjustment screw is too far into the stream. Try backing off the radius adjustment screw until the screw does not contact the water stream. If that doesn’t fix the dry spot try using a larger nozzle size in the rotors adjacent the dry spot. Unfortunately in most cases these simple efforts to fix the problem just result in creating a new problem. For example, using a larger nozzle may cause the pressure to drop and create the previously mentioned donut pattern problem. If new problems are created you will either need to live with dry spots, or spend some serious money making major repairs. Major repairs that are often needed include adding a booster pump to create more water pressure, relocating the rotors so that they are closer together, replacing the pipes with larger size pipes, or a combination of these.

Pop-Up vs. Shrub Style Heads

Rotor bodies come in two basic styles, “pop-up” and “shrub” style. Pop-ups do just what the name implies, the sprinkler body is installed below ground and the nozzle is lifted up above ground on a riser when the sprinkler is operating. After the irrigation is complete, the riser and nozzle are pulled by a spring back down into the sprinkler body. Since the body is typically installed below ground, the sprinkler becomes more or less invisible when it is in the “down” position. This has two advantages. The first is that the sprinkler does not detract as much from the appearance of the landscape. The second advantage is that the sprinkler is not as likely to trip someone, or be damaged by yard care equipment such as lawn mowers.

Recommended Pop-Up Heights

• Bermuda grass, dethatched yearly – use 3” or 4” pop-up.
• Bermuda grass, dethatched less often – use 4” pop-up.
• Fescue, bluegrass, rye grass – use 4”, 5” or 6” pop-up.
• St. Augustine or any grass planted near blowing sand – use 5” or 6” pop-up.
• Low ground cover – use 5” or 6” pop-up.
• Medium height ground cover – use 12” pop-up.
• Shrubs- see discussion below.

The 12 inch bodies work good for taller ground covers and low shrubs. Generally in a landscape design shorter shrubs are used at the edges of planters and larger, taller shrubs are used farther back in the area. So 6 or 12 inch pop-ups at the perimeter will often provide adequate coverage.

Shrub-Style Rotor Sprinklers

Shrub-style sprinkler bodies are mounted above ground level on a vertical pipe. This allows the sprinkler to be elevated above the level of the plants, where it can spray water over them. Shrub-type sprinklers are most often used in areas with tall, dense shrubs. Shrub-type bodies should not be used next to sidewalks, paths, driveways, lawn edges, or anywhere near places people walk or play. This is because the shrub sprinklers may trip people, or worse, someone may fall on one and be impaled (more likely just badly bruised, but the injury is still significant.) Not a pretty thought. For this reason I recommend, as do almost all professionals, that shrub-type spray heads only be used when there is no other option. If you have tall shrubs adjacent to a sidewalk you should consider replacing them with ground cover or lower growing shrubs. I use shrub-style sprinklers mostly on inaccessible hillsides where we are trying to grow plants for erosion control. I typically install them 36″ above ground to reduce problems with people tripping over them or falling onto them. Often I attach them to a large post to make them more visible. One of the arguments often given for using shrub style sprinklers is cost savings. Cost wise, I have found that shrub-style sprinklers are no less expensive than pop-up style bodies once you include the cost of the riser pipe and a stake to keep the sprinkler from wobbling. In order to make a shrub-style sprinkler cost less than a pop-up you must install it within 6″ of ground level. That is the height that makes it most dangerous.

A Brief History of Rotors

Nothing essential to read in this section, it’s provided for those who are curious. The earliest rotors were impact types, and Rainbird was one of the earliest sprinkler companies. Although several companies made similar products, the name Rainbird came to be almost synonymous with impact sprinklers. But impacts had problems in turf areas where pop-up style sprinklers are needed. The drive arms were large and to make a pop-up style of rotor required a huge case (called a bucket) for the sprinkler to retract into. They required a lot of maintenance because grass would grow into the cases and interfere with the arms. These large impact pop-ups are commonly are called “rat traps” in the industry. It was realized that a better solution was needed. In an attempt to create a smaller, closed-case (no exposed moving parts) rotor, cam and ball drive rotors were invented, primarily made by Buckner and a company named Safe-T-Rain. The “Safe-T-Rain” name resulted from the idea that their ball drive rotors were smaller than the impact rotors and presented less of a hazard. Both cam and ball drives also use an impact to turn the sprinkler, but now at least all the moving parts were smaller and internal. But they also wore out quickly and were never really widely accepted by the turf grass industry.

In the mid 70’s the first turbine powered gear-drive sprinklers came along. The Toro and K-Rain companies pioneered the gear drive industry. Toro used a sealed gear train filled with oil and their Toro S700 was the dominant residential size gear-drive for a number of years. They worked very well, but they were really difficult to adjust and the oil-filled gear boxes leaked oil and were expensive to manufacture. About the same time Rainbird introduced the very inexpensive, all-plastic Mini-Paw impact sprinkler. The Mini-Paw was smaller than other impact rotors due to a unique design of the impact mechanism. The Mini-Paw quickly became the biggest seller in the residential rotor market. Unfortunately the Mini-Paws didn’t hold up very well and had the standard impact sprinkler problem of high maintenance costs.

The next innovation in rotor design was water-lubricated gear-drives. These were inexpensive, reliable, and easier to adjust than the Toro models. Hunter, Nelson, and K-Rain quickly came to dominate the entire rotor market. Rainbird desperately needed a sprinkler to compete with these gear-drive rotors, and introduced the R-50, a variation of a ball-drive. The R-50 was a moderate success, but it was hard to adjust and the early models had a lot of maintenance problems. Rainbird then introduced the T-Bird, their first gear-drive rotor. It was essentially a first try and had problems. Finally, on the third try, Rainbird came out with the 3500 and 5000 series gear-drive rotors and belatedly joined the others. Now, finally, all the major irrigation manufacturers have a good gear-drive rotor available.

So what’s next for rotors? The latest innovation is the micro-rotor. This tiny rotor is the size of a spray sprinkler nozzle and fits on a standard spray sprinkler body. This makes it less than half the size of the other rotors, and much less expensive. Developed by the Walla Walla Sprinkler Company and sold under the name MP Rotator, this micro-rotor is a stream rotor type (multiple rotating streams of water.) It is driven by a turbine, but does not have a gear box. To keep the sprinkler rotating at a slow, steady speed it utilizes a sealed gel-filled clutch. The thick gel slows the speed of the nozzle. Rainbird recently introduced a mini-rotor also, and other manufacturer’s will follow. Only time will tell if this will be the next big thing in rotors.

What to Look for in a Good Quality Rotor

I recommend using a gear-drive rotor, or for smaller areas a turbine-driven micro-rotor. Pretty much all of the gear-drive rotors hold up well and perform well. The biggest problem with the gear-drive rotors is adjusting the arcs. Nelson makes the easiest to adjust but has a problem with the cap that covers the adjustment collars coming off. The Toro S700 has the hardest arc to adjust, and everyone else falls someplace in between. The bottom line is to be prepared to get wet when adjusting any rotor! The good news is that every one of the gear-drive rotors currently on the market has essentially the same basic features, so any of them will meet what I would consider the minimum requirements; a 3″ pop-up height, a good wiper seal, stainless steel retraction spring, sturdy plastic body and cap.

Rotor-Type Sprinkler Radius and Spacing

The radius of a rotor-type sprinkler is determined by the water pressure at the rotor inlet and the nozzle used. Most rotors come with several nozzles. More nozzles gives you better control and helps avoid over-watered areas. For a standard rotor you need to use a different nozzle for each arc, so you need one size nozzle for a 1/4 circle, another for 1/2 circle, another for 3/4, and another for full circle. So for even a simple sprinkler system you need at least 3-4 different nozzle sizes! If you also need different radius distances you will likely need even more nozzles. With stream rotors you don’t to use different nozzles for each different arc, so they don’t come with multiple nozzles.

The sprinkler manufacturer will list the radius for each sprinkler nozzle they make on the packaging, or on a separate reference chart (but please read the next paragraph before relying on that data.) Most also have performance data charts on their websites. The radius will vary based on the water pressure and flow, more pressure and flow will result in a larger radius. So for a typical nozzle you will see a table that gives the various radius, pressure and flow combinations for the nozzle (see example below.) If you can’t find the desired radius, get the nozzle with the next size larger radius than you need. The radius can be reduced by means of the radius adjustment screw on the top of the sprinkler nozzle. Some nozzles are designed to spray the water at a very low angle. Be careful of these nozzles, if you have mounded areas or hillsides they may spray water into the ground. It is best only to use low angle nozzles in relatively flat areas.

A big problem with all of the rotors is that they don’t perform as well in actual use as the manufacturer’s performance data tables suggest. The problem is that the radius the manufacturer measures on their indoor test range is not accurate out in the real world where the wind blows. Competition forces them to aim for the largest radius possible at the lowest possible pressure and flow. But the gallonage and pressure have a huge effect on how effectively the water is distributed. For example, a low gallonage, low pressure nozzle is going to be much more effected by wind (even wind so slight you don’t even notice it) than a higher flow, higher pressure nozzle. So you need to be careful. Unfortunately it takes lots of experience to know what works and what does not. Because of competition, the advice you get from the manufacturer’s literature and help lines has, in my opinion, stretched the limits considerably. So, based on my experience I am providing you with nozzle GPM/pressures combinations I recommend you use for various situations. I very strongly suggest that you follow these recommendations. In some cases I have provided more specific recommendations in my reviews. If you don’t follow them you may very well regret it! Many people before you have made this mistake, please don’t join them. Fixing the problem if you use the wrong nozzles can be very expensive! People are really unhappy when I tell them what is needed to fix the problem.

As a general rule I advise against spacing rotors more than 45 feet apart unless you have a professional irrigation consultant design the system. Most contractor’s and “free design services” don’t have the design knowledge to handle a design of this complexity, you need to find a designer with lots of experience. I’m not trying to make anyone look bad, I just have a lot of experience fixing problems on these large radius systems, and have noted that the problems almost always resulted from poor original design. Wide spacings simply bring many difficult design problems with them.

Important! Rotors require what is know in the industry as “head-to-head spacing”. Head-to-head spacing means that the water from one sprinkler must spray all the way to the next sprinkler in all directions- to the right, left and also to the head(s) across from it. This is very important, spacing the sprinkler heads too far apart is one of the most common design errors, and it is almost impossible to go back and correct the problem later without spending tons of money. Simply stated if the radius is 30 feet you need to space the rotors no more than 30 feet apart, less in many cases. The sprinkler design tutorial gives a more in-depth description of the importance of head-to-head spacing. Head-to-head spacing is critical for avoiding dry spots and disease problems. With spacings wider than 45 feet it is often necessary to use spacings even closer than head-to-head.

Matching Precipitation Rates

Standard rotors (the water stream moves back and forth) require a little more design effort. To make this easier I have suggested which nozzles you should use in many of my reviews of specific rotors. In those cases you should simply use the nozzles I recommend. You should also use the free on-line Sprinkler System Design Tutorial when you actually design your system! This is just background information, the tutorial will guide you through the design process step-by-step. However, this information will help you understand why it is important that the rotor you choose to use should come with a large selection of nozzles.

The precipitation rates for standard rotors are not matched, so you must select the right nozzle size for each rotor based on the radius, pattern, and flow of the various nozzles available. Here’s an example of a performance chart for a typical standard rotor. (Don’t actually use this chart, it is just a sample! Each brand and model has it’s own chart, you need to use the correct chart.)

Sample Rotor Nozzle Performance Chart

The chart above shows four nozzles (for many rotors there will be more nozzles available.) For each nozzle it gives the radius and GPM combinations that result at different water pressures. Remember this is the water pressure at the sprinkler, which will be less than the water available water pressure due to pressure lost in the pipe and valves.

Let’s consider a 60 foot x 60 foot square lawn area (see image below.) Nine rotors would be required to water this area as follows: In each of the four corners there would be a 1/4 circle rotor (4 total). At the mid-point of each side there would be a half circle rotor (4 total). In the exact center of the lawn there would be a single full circle rotor. Each rotor would need a radius of 30 feet. This would provide the desired head-to-head spacing.

Rotor Spacing Example for 60′ x 60′ Lawn
(Using 30′ Radius Rotors)

Yes, this is how many rotors you need to water a 60 foot square lawn! No need to write and ask me if I made a mistake. Nope, I don’t get kick-backs from the sprinkler companies for helping them sell more sprinkler heads. There are a number of good reasons for all the overlap, if you really are interested you can take a couple of classes at your local university in physics and hydraulics. OK, I’m guessing that doesn’t sound very interesting to you, so let’s just move on.

As you recall from the description of a standard rotor, the rotor shoots a stream of water that rotates one way around the rotor, then reverses back the other direction, covering the same area again (except for a full circle rotor, which just moves continuously in a circle.) This back and forth motion creates a problem- since all the rotors turn at the same speed. So in the time it takes the full circle rotor to make one complete rotation, the 1/4 circle rotor will have gone back and forth over the same area 4 times. So if you use the same size nozzle in all the rotors the area watered by the quarter circle rotor would have 4 times more water applied to it than the area watered by the full circle rotor. This will not work! The area around the corners would turn to mud while the area in the center of our lawn would be dry! Therefore, to compensate we use a smaller nozzle in the corners and a larger one in the center. The full circle nozzle will need to have a GPM four times higher than that of the quarter circle. Using our 60 foot square lawn and the Sample Rotor Nozzle Performance Chart above we would select the following nozzles:

One thing you will notice is that these nozzles are not a perfect solution. To be perfect, all the radii would be identical and the GPM values would be exact multiples of each other (ie; all radii would be 30 feet and GPM values would be 1.1, 2.2, 3.3, and 4.4 GPM.) Unfortunately perfection is not attainable, so we must settle for the next best thing. In this case the GPM values are close enough to being multiples of each other. Because the radii are all larger than we need, it will be necessary to reduce the radius of each rotor after it is installed by using the radius adjustment screw. Now you can understand why a rotor that includes a lot of nozzles is better than one that only includes one nozzle. If you go to a typical discount retail store you will find a lot of rotors that only come with one nozzle. Now you know why that is not such a good deal for most yards. No doubt a lot of you are thinking to yourself, “so that’s why the middle of my yard is as dry as an old bone and the corners are swamps!”

Stream rotors have matched precipitation rates, so you don’t have to deal with the different nozzles for different arcs problem. If you are designing with them you will use the same nozzle for all the sprinklers that have the same radius. A chart provided by the manufacturer will tell you the GPM for each rotor based on the pattern used (ie; quarter circle, half circle, full circle.) This makes designing with stream rotors a bit easier than with standard type single stream rotors. Select stream rotor nozzles based on the radius desired. Most stream rotors do not have a radius adjustment feature, so the radius can’t be changed except by changing the nozzle. Here’s an example of a nozzle chart for a stream rotor:

Sample Stream Rotor Nozzle Performance Table

From the nozzle chart you start by selecting the radius you want. The table tells you the pressure you will need and the GPM that the sprinkler will require. So if you need a 21 foot radius you would select nozzle #02. The chart then tells you that you will require 35 PSI at the rotor and for a half circle pattern (180°) the flow used by the rotor will be 1.44 GPM.

Special Situations

Most rotor-type sprinklers are available with a number of optional features. Here are some situations where you should consider using a rotor sprinkler with optional features.

Slopes & Check Valves. If your yard is sloped you should use sprinklers with built-in check valves. An elevation change that exceeds the depth of your pipe is enough to make the use of check valves advisable. In other words, if one side of the yard is more than a foot lower than the other, and you plan to bury the pipes less than a foot deep, you should use check valves. I use them on all my projects as the default. Most manufacturer’s built-in check valves will work up to an elevation difference of 10 feet height. If the elevation difference between sprinklers is greater than 10 feet you will need to add an additional adjustable low-drainage prevention check-valve under the sprinkler. The purpose of the check valves is to prevent the water from draining out of the pipes through the lowest sprinkler head each time the water is turned off (this is called “low-head drainage”.) Low head drainage creates mud pits around the lowest heads, and also allows water to drain onto sidewalks causing algae and moss to grow. Plus each time you start up a valve zone the sprinklers will sputter and spit as the air is pushed out, which is bad for the pipes, hard on the sprinkler, and wastes water.

If you use check valves and you are in a cold winter area where you winterize your sprinkler system, you need to have your sprinkler system winterized by blowing the water out of pipe with air. Another option is to remove the check valves before you winterize the system, however this is a lot of work. The check valves trap the water in the pipes and the sprinkler heads where it will freeze and break the pipes and the sprinkler heads.

Play areas. When using rotors in play areas you should use rotors with rubber covers. The rubber cover helps reduce injuries caused when someone falls on the sprinkler.

Extremely sandy soil. Some rotors are available with stainless steel sleeves around the pop-up riser. This helps keep the riser from becoming scratched by sharp sand particles. Deep scratches in the plastic can prevent the riser from easily moving up and down. Generally this is not a big problem except in very sandy areas.

Recycled (also called reclaimed) water. When using recycled water the rotor should be equipped with an optional purple-colored cap. Recycled water is usually treated sewage or grey water (wash water.) Many cities are now installing separate water systems that carry recycled water for use with irrigation systems, especially in areas where water is scarce. In general, human contact with recycled water should be avoided. The purple color is the universal identifier of the presence of recycled water.

In order to make good decisions about which products will work best for you it is necessary to have some basic knowledge of how sprinklers work and what the various options available to you are. Therefore the following few paragraphs are intended to give you the background necessary to understand the terminology used in my reviews. The background information below is much more in-depth than that in the tutorials, so even if you have read the tutorials you should still look through this page.

Fixed Spray-Type Sprinkler Basics

Sprinklers fall into one of two types based on the method they use to apply water to the ground; fixed spray-type (sprays) or rotor-type (rotors.) Spray-type sprinklers are the type of sprinkler that spray a fixed water pattern similar to how a old-fashioned shower head works. Rotor-type sprinklers use a rotating stream (or multiple streams) of water to apply the water to the ground. Spray-type sprinklers are also called “fixed spray heads”, “spray heads” and often just plain “sprays”. Most of the professionals I know call them “spray heads”, and you will note that is the term I use also. They are typically used for smaller size areas. Rotor-type sprinklers are used for larger areas (generally more than 18′ in width.)

Where should spray heads be used?

Spray heads work best for smaller areas and areas with tight, curving edges. I like to use them for anything less than 25 feet wide. Although rotors are available for areas as narrow as 18 feet, spray heads tend to be more economical in these smaller areas than rotors. Another advantage of spray heads is their relative simplicity. There is not a whole lot to go wrong with one. By far the most common problems result from clogged nozzles, a problem that can be almost totally eliminated by flushing the pipes thoroughly prior to installing the spray heads and installing a filter on your sprinkler system. (Install the filter upstream of the automatic sprinkler system valves so the valves benefit from filtered water too!) Although most spray heads come with a small filter screen that installs under the nozzle, in my opinion these filters are not sufficient. I recommend installing a 100 mesh filter at the water source for ALL sprinkler systems.

How a Typical Spray-Type Sprinkler Works

Water enters the base of the sprinkler and passes up through the body to the nozzle. On the way to the nozzle the water passes through a filter screen. As previously mentioned I do not suggest that you rely on this screen for filtration, consider it a backup to your sprinkler system filter. Do not remove the filter screen, some spray type sprinklers will not work properly without the screens! After passing through the screen the water enters the nozzle and passes through a small valve. This valve is operated by a screw on top of the nozzle, which is known as the “radius adjustment screw”. As you turn the screw the valve closes slightly. This causes the water to speed up as it tries to force it’s way through, resulting in an increase in turbulence and friction. This turbulence and friction causes a drop in the water pressure. The pressure drop in turn causes the radius of the sprinkler to be reduced. From the radius adjustment valve the water continues up into the nozzle and is sprayed up against a plate or through a small slit(s), which causes the water to fan out as it leaves the nozzle. This is what creates the fan-like spray pattern typical of a spray head. The shape and size of the plate or slit is what determines the nozzle pattern and angle. Some spray nozzles have adjustable plates or slits that allow the spray arc to be adjusted.

A typical spray head consists of two separate parts, a body and a nozzle. Often these are sold separately, but sometimes retail stores package them together. Typically various different nozzles are available, anywhere from just a few different patterns and radii combinations, up to hundreds of variations. In most cases all of a manufacturer’s nozzles will fit on all of their spray head bodies.

Pop-Up vs. Shrub Spray Heads

The bodies come in two basic styles, “pop-up” and “shrub” style. Pop-ups do just what the name implies, the sprinkler nozzle is attached to a riser which lifts the nozzle up into the air when the sprinkler is operating. After the irrigation is complete, the riser and nozzle drop back down into the sprinkler body. Since the body is typically installed below ground, the sprinkler becomes more or less invisible when it is in the “down” position. This has two advantages. The first is that the sprinkler does not detract as much from the appearance of the landscape. The second advantage is that the sprinkler is not as likely to trip someone, or be damaged by yard care equipment such as lawn mowers.

Recommended Pop-Up Heights

• Bermuda grass, dethatched yearly – use 3” or 4” pop-up.
• Bermuda grass, dethatched less often – use 4” pop-up.
• Fescue, bluegrass, rye grass – use 4” or 6” pop-up.
• St. Augustine or any grass planted near blowing sand – use 6” pop-up.
• Low ground cover – use 6” pop-up.
• Medium height ground cover – use 12” pop-up.
• Shrubs- see discussion below.

The 6 inch height bodies are the primary height I use for my projects in both lawn, shrub, and most ground cover areas (I use a lot of low growing ground covers with 4-6 inch mature height.) The 12 inch bodies work good for taller ground covers and low shrubs. Keep in mind that with shrubs you don’t always need to throw the water over the top of the shrub. When the shrubs are first planted they are small and a 6″ height will spray over them. As the shrubs grow they begin to block the spray, but by this time the shrub has developed a good root system and will seek out the water. Generally in a landscape design shorter shrubs are used at the edges of planters and larger, taller shrubs are used farther back in the area. So 6 or 12 inch pop-ups spaced 10 to 12 feet apart at the perimeter will usually provide adequate coverage.

Shrub-Style Spray Sprinklers

Shrub-style sprinkler bodies are mounted above ground level on a vertical pipe. This allows the sprinkler to be elevated above the level of the plants, where it can spray water over them. Shrub type sprinklers are most often used in areas with tall, dense shrubs. Shrub type bodies should not be used next to sidewalks, paths, driveways, lawn edges, or anywhere near places people walk or play. This is because the shrub sprinklers may trip people, or worse, someone may fall on one and be impaled (more likely just badly bruised, but the injury is still significant). Not a pretty thought. For this reason I recommend, as do almost all professionals, that shrub type spray heads only be used when there is no other option. If you have tall shrubs adjacent to a sidewalk you should consider replacing them with ground cover or lower growing shrubs. I use shrub style sprinklers mostly on inaccessible hillsides where I am trying to grow plants for erosion control. I usually install them 36″ above ground to avoid problems with people tripping over them or falling onto them. One of the arguments often given for using shrub style sprinklers is cost savings. Cost wise, I have found that shrub style sprinklers are no less expensive than pop-up style bodies once you include the cost of the riser pipe and a stake to keep the sprinkler from wobbling. In order to make a shrub style sprinkler cost less than a pop-up you must install it within 6″ of ground level. That is the height that makes it most dangerous. Your homeowner’s insurance rates will likely go through the roof if someone trips on a sprinkler and files a claim for injuries. This will be far more expensive than the cost would have been to use pop-up sprinklers!

Spray-Type Sprinkler Radius

The radius of a spray-type sprinkler is determined by the nozzle used. The sprinkler manufacturer will list the radius for each sprinkler nozzle on the packaging, a separate reference chart, or their website. The radius will vary based on the water pressure, more pressure will result in a larger radius. So for a typical nozzle you will see a table that gives the various radius, pressure and flow combinations for the nozzle (see example below.) Most spray head nozzles have a radius between 4-15 feet, some are claimed to have a radius as great as 21 feet, but I would urge caution using a radius over 15 feet. It’s a physics problem, water simply doesn’t spray further than 15 feet very well or evenly. When selecting a nozzle, look for one with a radius as close to your desired radius as possible. If you can’t find the desired radius, get the nozzle with the next size larger radius than you need. The radius can then be reduced by means of a radius adjustment screw on the top of the sprinkler nozzle. As the adjustment screw is closed, the water pressure at the nozzle is decreased, this results in the radius and flow of the sprinkler being reduced. For example, if you wanted to water a 14 foot wide area you would install a 15 foot radius spray head and use the radius reduction screw to reduce the radius to the desired 14 feet. With most nozzles the radius can be adjusted down to almost nothing, however I don’t recommend reducing it by more than about 40% when using the radius adjustment screw. Further reduction can cause coverage and operation problems. Often times a nozzle with a severely reduced radius will stop working on warm days. This is because the heat causes the radius reduction screw to expand, which causes the flow to be completely shut off. One last thing to watch for when selecting a nozzle is the angle of spray. Some nozzles are designed to spray the water at a very low or even flat angle. Be careful of these nozzles, if you have mounds or hillsides they may spray the water into the ground. It is best only to use low angle nozzles in flat areas.

Spray-Type Sprinkler Spacing

As a general rule I advise against spacing spray-type sprinklers more than 18 feet apart. Spacing them farther than that often gives unsatisfactory results. Spray heads require what is know in the industry as “;head-to-head spacing”. This means that the water from one sprinkler must spray all the way to the next sprinkler in all directions– to the right, left and also to the head across from it. This is very important, spacing the sprinkler heads too far apart is one of the most common design errors, and it is almost impossible to go back and correct the problem later without spending tons of money. The sprinkler design tutorial gives a more in-depth description of the importance of head-to-head spacing. Head-to-head spacing is critical in lawn areas for avoiding dry spots and disease problems. In shrub and ground cover planting there is more room for fudging, you can generally space the heads at up to 60% of their diameter of water throw. Examples: Using a 15′ radius head for lawn areas you should not exceed 15′ between sprinklers. Using 15′ radius spray heads for shrub areas you should not exceed 18′ (30′ diameter x 0.6) between sprinklers.

Sample Spray Nozzle Performance Table (this sample is for a Toro nozzle)

Pattern	Part No.	20 PSI	30 PSI	40 PSI	50 PSI
	12Q	11′ – 0.40 GPM	12′ – 0.50 GPM	13′ – 0.60 GPM	13′ – 0.63 GPM

Example: From the chart above you can see that this nozzle at 30 PSI will have a radius of 12 feet and a flow of 0.50 GPM (gallons per minute). If you wanted to operate this nozzle at 25 PSI you would need to extrapolate the data from the chart. For example for this nozzle 25 PSI would give 11.5′ radius and 0.45 GPM flow.

Reducing the radius of a nozzle.

As previously noted you can reduce the radius of most nozzles using the radius reduction screw. This allows you to use the nozzle in a smaller area. A common question I am asked is what happens to the flow of the nozzle when you decrease the radius? The answer is that the flow (GPM) is reduced, but not by much. In most cases you can just ignore it and use the full radius flow. If you really want to find out how much the flow would be reduced, simply refer back to the manufacturer’s performance chart for that nozzle. As previously mentioned, the radius reduction screw works by reducing the water pressure in the nozzle. If you look at a performance chart it will give you the radius at various pressures. Make sure you are using the right chart for the nozzle you plan to use. Find the radius on the chart that you plan to create using the radius reduction screw. The chart will show you the flow the nozzle uses at that radius.

Example: Let’s say you install the nozzle shown in the table above in a situation with 30 PSI, but you only want it to throw 11 feet. You would use the radius reduction screw to reduce the radius to 11′. According to the chart at an 11 foot radius the nozzle would use a flow of 0.40 GPM.

Matched Precipitation Rates

Most spray heads now have what are called “matched precipitation rates”. Matched precipitation (ppt) rate nozzles mean that the nozzles can be mixed and matched on the same sprinkler zone without concern that one might apply more water than another. Back in the bad old days, only nozzles with the same radius were matched. So you had to use all the same radius nozzles on each valve circuit. But now with matched ppt rate nozzle sets, you can use the radius that works best. So you can use 8 foot, 12 foot, 15 foot, and strip nozzles on the same valve circuit and you will still get nice uniform coverage (provided you don’t exceed head-to-head spacing, that is!) You don’t even begin to know how much easier this makes designing a sprinkler system! There are two exceptions you need to keep in mind however. First, only those nozzles in a manufacturer’s set that are labeled “matched precipitation” are matched. Most manufacturer’s also make nozzles that are not matched to the others. So make sure they are labeled “matched precipitation”. Second is that all the nozzles must be made by the same manufacturer. Each manufacturer uses a different precipitation rate as the default one for the nozzles to match. So don’t mix manufacturer A’s nozzles together with manufacturer B’s nozzles on the same valve zone, even though they both may be labeled “matched ppt”.

Misting and Fine Tuning:

All spray-type sprinklers will mist and waste water if the water pressure exceeds the levels listed in the performance data tables. Some misting is normal. To determine if the misting is excessive adjust one sprinkler as follows:

• Turn the radius reduction screw on the nozzle until the radius is less than head-to-head coverage.
• Now open it back up until head-to-head coverage is obtained.

The sprinkler is now operating efficiently, and you will be able to observe the normal level of mist. If all the heads are misting too much, you should use the flow control on the valve rather than the radius reduction screws to reduce the misting. Simply follow the steps above, but close and open the valve flow control rather than the radius reduction screw. If only a few are misting, use the radius reduction screw on the sprinkler.

Special Situations

Most spray-type sprinklers are available with a number of optional features. Here are some situations where you should consider using a spray-type sprinkler with one of these optional features.

• Slopes. If your yard is sloped you should use sprinklers with built-in check valves. An elevation change that exceeds the depth of your pipe is enough to make the use of check valves advisable. So if you are installing the pipe 12″ deep, and one side of the watered area is 18″ higher than the other, you should use check valves. I use them on all my projects as the default, they aren’t very expensive. Most manufacturer’s built-in check valves will not work if the elevation difference is greater than 10 feet. If the elevation difference between sprinklers is greater than 10 feet you will need to add a separate adjustable low-drainage prevention check valve under the sprinkler. For built-in check valves look for sprinklers with the “CV” feature in my list of sprinkler features.
• Radius under 6 feet. If you are reducing a nozzles radius to less than 6′ consider using an optional Pressure Control Disc to reduce the radius rather than using the built-in radius reduction screw. This does not apply to nozzles that are designed to spray less than 6 feet such as strip sprays and short radius nozzles. It only applies when you plan on using the radius reduction screw to reduce the radius of a nozzle that is designed to throw more than 6 feet. Look for sprinklers with the “PCD” feature in my list of sprinkler features.

Optional Features

Check Valves (CV). The most popular option for spray heads are built-in check valves. If your sprinkler system is being installed in an area where the elevation change exceeds the depth you are burying the pipe you should probably use sprinklers with this feature. Example; if the elevation change is 10 inches and you are burying the pipes 6 inches deep, you should use check valves. But in this same situation if you were burying the pipes 12 inches deep you would not need them.

The check valve prevents water from draining out of the pipes through the sprinkler head after the valve closes. When the water drains out of the pipes it is replaced with air. The next time you turn on the sprinklers this air must be expelled from the pipes, so for the first couple of minutes the sprinklers spit and spew air. This puts a lot of stress on the pipe and the sprinklers. As the water rushes into the pipes it slams into the ells and tees where the pipe changes direction. The air also messes up your uniformity as some sprinklers are watering the lawn while others are just blowing air out! The last problem is that the water that drains out of the sprinkler heads after the valve closes has to go somewhere. So it either runs across a sidewalk or driveway and grows moss and mold, or it makes a big mud puddle around the sprinkler head.

There is one large misunderstanding in the industry about check valves that you should be aware of. Many people, even professionals, erroneously believe that check valves will prevent water from running out of the heads if the valve leaks. This is absolutely not true. If the valve is leaking when it is closed, water will still run out of the lowest head, even if you have check valves installed in the head. This is because the water leaking from the valve is pressurized, and the pressurized water has sufficient energy to force open the check valves. The bottom line is that if you have a leaky valve, the water is going to come out of one of the sprinkler heads and check valves will not stop that. Now this is such a prominent “urban sprinkler legend” that I know a few people out there are going to want to argue with me about it. So before you fire off an angry email to me please test it out yourself. Install a valve zone with check valves on all the heads. Then open the valve just a tiny bit, just as if it were leaking. Now check out the water leaking out of the heads!

Pressure Control Discs. These small disks fit into the bottom of the nozzle or are built into the screen. They are essentially a rubber disk with a small hole in it that restricts the water flow. They control the water pressure and flow into the nozzle. As the water pressure presses against the soft rubber of the disc, the disc deforms and the hole gets smaller, thus reducing the flow through it. They are very handy for reducing the radius of a spray-type sprinkler as they work much better than the radius reduction screws on the nozzles. The sprinkler manufacturer will have a chart showing which disc to use with each nozzle to give the exact radius you need. You will probably need to go to an irrigation specialty stores to purchase these. The Pressure Control Discs can be easily retrofitted into existing sprinklers.

Other available features and options for spray-type sprinklers are described on the spray sprinkler listing page.

Why a Filter?

Water filtration is important for all irrigation systems. Now before someone argues with me, yes, some sprinkler systems are used to spread solids, such as treated sewage, for disposal. But even those in my experience have incorporated some form of filtration upstream of the system to prevent solids which are too large from entering the system.

Filters can help extend the life of, and lower the maintenance on, your sprinkler system. For drip systems they are a necessity to prevent emitters from becoming plugged. Even if small sand particles can pass through your system without clogging it, they cause wear on the equipment. Automatic valves contain very small water passageways in them which can become plugged resulting in the valve failing to either open or close. A small grain of sand caught in a spray nozzle can result in a dry, dead spot in a lawn.

While sand is probably the first thing most people think needs to be filtered out of the water, organic materials can be just as important to remove. Algae can grow inside the system, especially in drip tubes. Another situation occurs when a small piece of organic matter snags somewhere in a valve, fitting, emitter, or sprinkler. The organic matter by itself may not be large enough to be a problem. But soon another piece comes along and gets caught in the first. Then a very small grain of sand that would normally have passed through the system without problems becomes caught in the organic matter. Soon a large build-up of crud forms and the flow is blocked. Have you ever had the hose on your vacuum cleaner clog up with a wad of hair, small objects, and dirt? Each one of those objects went into the hose, so they should have made it through to the canister. But they didn’t because they all got caught together. The same thing happens in your irrigation system. How about a small fish or a clam? They go into your system when they are small (often as eggs) and once in there they grow! Laugh if you want, but I’ve seen it many times! Freshwater clams are very common in city water systems. That’s right, there’s a very good chance that every time you get a drink from the faucet you’re drinking clam water! Yuck… (but be realistic, has it killed you yet? Or perhaps you’ve never eaten clam chowder? Or maybe you should take a look in your cat or dog’s bowl at what THEY drink without getting sick. The truth is that your body processes dirt much better than your irrigation system does!)

Types of Filters

Filters are broken down into different categories dependent upon the method used to filter the water. A brief description of the most common types follows.

Screen filters:

Screen filters are probably the most common filters and in most cases the least expensive. Screen filters are excellent for removing hard particulates from water, such as sand. They are not so great at removing organic materials such as algae, mold, slime, and other unmentionables! These non-solid materials tend to embed themselves into the screen material where they are very difficult to remove. In other cases they simply slide through the holes in the screen by temporarily deforming their shape.

Screen filters are cleaned by flushing them with a stream of water or removing the screen and cleaning it by hand. Depending on the flush method used you will probably have to periodically hand clean the screen to remove garbage not removed by flushing. Several methods of flushing are common. The simplest is a flush outlet. The outlet is opened and it is hoped that the debris washes out of the flush outlet with the water! An improved variation on this is the directed-flow flush. Again a flush outlet is opened, but in this case the structure of the filter is designed so that the flush flow rushes over the face of the screen sweeping the debris along with it. Somewhat like hosing off a sidewalk with a strong stream of water. This is the most common method found in inexpensive filters. The most effective method of flushing is the backwash method, but these filters are typically more expensive. In this method the flush water is forced backwards through the screen for a very effective cleaning. This is accomplished by either using two filters side-by-side (the clean water from one is used to flush the other) or by “vacuuming” the screen with a small nozzle which is moved over the screen by a mechanism in the filter, “sucking” the debris off of it. (Although it is referred to as vacuuming it is really a form of backflush. The water is forced backwards through the screen by the water pressure in the system, not by a true vacuum.)

Cartridge Filters:

Cartridge filters are essentially a variation of the other types listed here, depending on what the cartridge is made of. Most cartridges contain a paper filter which works just like a screen filter. Most also remove organics well because the paper texture is rough enough to snag the organic matter. While some cartridges can be washed, most of them you simply replace when dirty.

Media Filters:

Media filters clean the water by forcing it through a container filled with a small, sharp edged, “media”. In most cases the media material is uniform sized, crushed sand. The water passes through the small spaces between the media grains and the debris is stopped when it can’t fit through these spaces. Media filters are best for removing organic material from the water. This is where the importance of the sharp edged media comes into play. These sharp edges snag the organics which would otherwise slime and slither their way through the small spaces. This is why it is important to use sharp media. Whenever someone tells me their media filter doesn’t work my first question is always “where did you get your media material for the filter?” Their answer is almost always something to the effect of “uh…, I just used some sand from the creek up the road, why?” River, beach, and creek sand tend to have rounded, soft edges and are not suitable at all for media filters! Media filters are the type of filters most commonly used for high volume cleaning of water from rivers and lakes. They are used by both large farms and municipal water systems. They most often are 3 to 6 foot diameter rounded tanks sitting on short legs, and are almost always in groups of two or more. I’ve seen municipal water systems with media filters that are over 12 feet tall and 10 feet in diameter! They tend to be a wee bit large and heavy for the average homeowner! Media filters are cleaned by backflushing. The force of the water going backwards through the filter lifts and separates the media which frees the debris and washes it out through a flush valve. Because a small amount of media is often washed out too, it is necessary to periodically add some more to the filters. Because sand is not easily flushed out of them, media filters are not good for situations where the water contains a lot of sand. The sand will not flush out and soon the filter will be completely filled with sand which you will have to remove by hand. Media filters must be carefully matched to the system flow rate for proper operation. Always consult the media filter manufacturer’s literature for proper sizing procedures!

Disk Filters:

Disk filters are a cross between a screen filter and a media filter, with many of the advantages of both. Disk filters are good at removing both particulates, like sand, and organic matter. A disk filter consists of a stack of round disks. The face of each disk is covered with various sized small bumps. A close up view of the bumps reveals that each has a sharp point on the top of it, somewhat like a tiny pyramid. These bumps are very small, thus a typical disk looks a lot like the old vinyl 45 RPM records! Because of the bumps, the disks have tiny spaces between them when stacked together. The water is forced between the disks, and the particulates are filtered out because they won’t fit through these gaps. The organics are snagged by the sharp points on the bumps. For automatic cleaning of the filter the disks are separated from each other which frees the debris to be flushed out through a flush outlet. For less expensive disk filters you must remove the disks and hose them off.

Centrifugal Filters:

Also known as “sand separators”, centrifugal filters are primarily for removing particulates, such as sand, from the water. They are great for situations where a lot of sand is present in the water as they don’t clog up nearly as quickly as other types of filters. The dirty water enters the filter where it is swirled around the inside of a cylinder. The centrifugal force causes the sand particles to move to the outside edge of the cylinder where they gradually slide down the side to a holding tank at the bottom. Centrifugal filters are reasonably inexpensive, very simple, and are very effective for removing sand from water. Because many wells pump sand up along with the water you will often see a centrifugal filter installed on a large well. Some centrifugal filters are designed to be installed inside the well. These typically are attached to the bottom of a submersible pump. It is not unusual for a very small amount of sand to pass through a centrifugal filter. For drip irrigation systems I always add a “backup” screen filter when using a centrifugal filter as a safety precaution. A centrifugal filter used in combination with a media filter after it is an excellent combination. The centrifugal pulls out the sand, the media filter then removes the organics. This combination is very often used in municipal water treatment, where a third activated charcoal filter may be added to remove chemicals. Note that the centrifugal filter selection must be carefully matched against the system GPM or the filter will not work correctly. Always consult the manufacturer’s sizing guidelines when designing a centrifugal filtration system for your irrigation system.

Tutorial continues below…

Filter Recommendations

So which filter to use? There is no fixed answer. Your budget, water quality, and availability of the filter and parts must all be considered. Screen filters are generally the least expensive. If you have a city water supply with nothing more than a periodic grain of sand or flake of rust in it, a screen filter will be fine in most cases. Sometimes a combination of more than one type of filter will be needed. For a smaller size system a disk filter would remove both sand and organics, but you might need to frequently clean it! Here are some suggestions based on the source of your irrigation water:

How much Filtration do you need?

What we are asking here is what’s the smallest size of particle that needs to be removed from the water by the filter? The amount of filtration you need is dependent to a large degree on what type of irrigation you have. For example, drip irrigation systems need a much higher degree of filtration in order to protect the emitters from plugging. For most applications the amount of filtration is measured by the “mesh size” of the screen or maximum size in “microns” of an object that can pass through the filter. There is a mesh vs. micron conversion table at the bottom of this page.

You always want to use the highest level of filtration that is practical. Even if your sprinkler system can easily handle a fairly good size grain of sand without clogging, removing that sand grain is still advantageous as it will eliminate the wear on the system caused by the sand grain as it passes through. The balancing factor is that the more particles removed the more often the filter clogs up and needs to be flushed. Excessive flushing can waste water and energy, so a trade off is necessary.

Rule of Thumb Guidelines

Drip Systems:

The drip emitter manufacturer will specify in their literature the level of filtration required. I almost always take it one level greater. (That is, I remove even smaller particles than they recommend.) I generally never use anything less than 100 mesh or 150 micron.

Sprinkler Systems:

A 70 mesh filter will remove most particles capable of plugging a sprinkler nozzle, however, I like to use a 100 mesh (150 micron) and often use a 150 mesh (100 micron) filter in order to also remove the particles that can cause wear on the system and damage the valves.

All Irrigation Systems:

Bottom line- I would suggest using at least a 100 mesh (150 micron) screen or equivalent in the filter. I suggest you run the water through a filter before it reaches the control valves. Small grains of sand are one of the most common causes of control valve failure, especially when using the standard electric solenoid valves used on most irrigation systems. My experience is that the savings in valve repairs will pay for the cost of the filter over the next 5 years. With a cost benefit like that it is pretty hard to argue against installing a filter!

Approximate Filter Size Equivalents

The values in the table above are rough equivalents. While the Micron is a standard metric measurement, the term Mesh is rather subjective, especially for values over 300. For example, I’ve seen both 500 mesh and 700 mesh screens that have equal filtration, that is, they both filter out particles down to 30 microns in size. The problem is related to the size of wire from which the screen is manufactured. The mesh designation is based on the number of wires in one linear inch of the screen. So two screens can have the same mesh, but if one is made with thicker wire than the other, the one with thicker wire will have smaller openings between the wires. Therefore, micron is a much more accurate measurement for use in determining the size of particle that can (or can’t!) pass through a filter.

This page is part of the Pump Tutorial Series.  The 1st page is at  Pumps: Selecting-a pump step-by-step.

If you have an existing pump and want to design an irrigation system that uses it as the water source,  the Irrigation Design Tutorial will take you through the process.  Rather than rewrite the entire tutorial on how to design and irrigation system we’ll just send you over to the one that is already written!  It will show you exactly how to test your existing pump to determine the flow and pressure output.  Then it will take you through the process of designing an irrigation system to use your existing pump, including some tips and tricks that are just for use in designing irrigation systems that use pumps!

Continue reading Designing a Irrigation System to Use a Existing Pump →

This landscape sprinkler and drip/trickle installation tutorial will take you step-by-step through the process of constructing (or assembling) your new sprinkler irrigation system.  During the process you will learn a lot of tricks as well as how to “speak irrigation talk” which can be helpful when you are working with others in the industry.  Why speak the lingo?  Well for example when buying your materials it is a quicker if you can say “I need a three-quarter by three-quarter by half slip-slip-thread tee” rather than “I need a outlet thingy to go on my pipe to connect a sprinkler to it.”  That first description may seem confusing to you now, but you will know exactly what it means very soon.  We’ll also give you some checklists and forms you can use to make this all easier and save a lot of trips to the store to pick up stuff you forgot.

Quick reminder, if you haven’t designed your sprinkler system yet you need to do that before you continue.  See the Sprinkler System Design Tutorial.

Sprinkler System Installation Tutorial
Table of Contents

1. Creating Your Shopping List of Materials (aka a “Take-Off”.)  Creating a complete and accurate “take-off” is the first step to install your irrigation system. This section tells you how to do it right!
2. Take-off Form. A easy to use fill-in-the-blank form that lists the most common materials used in the installation of drip irrigation and sprinkler systems.
3. Fittings take-off Form.  A ready to use form that lists the most common PVC fittings used when installing a sprinkler or drip irrigation system.
4. Checklist.  A checklist of items commonly needed to install a sprinkler or drip irrigation system.  Review it before heading to the store!
5. Understanding Fittings.  A complete guide to common PVC fittings, including the correct terminology to use when describing them to others. Includes sketches of each fitting.
6. Sprinkler Risers. The sprinkler riser plays a large part in determining how often you will need to repair broken sprinklers!
7. Anti-Siphon Valves. The most common valve type for residential irrigation systems.
8. Globe-Valve Installation.  The most common valve type used for commercial irrigation systems.
9. Miscellaneous Installation Details.  Lots of sketches showing how to fit it all together!  Don’t guess how to put it together, save tons of time using these!
10. Irrigation Installation Tools.  Tools and tips for using them that make the job easier.
    OK, time to get outside and start kicking up dirt!
11. Layout Your Irrigation System.  Mock up the system.  Make sure you have everything, check for design errors before you start digging!
12. How to Make a Leak Free Threaded Pipe Connection.  How to connect threaded pipe ends so they won’t leak.
13. Safety First!  A list of safety precautions and tips to make the job more pleasant.
14. Connect to Water Supply. How to tap into the water supply.
15. Install Underground Piping. Tips for installing the piping and wire.
16. Backfill & Flush. Proper flushing is critical to your system’s survival.
17. Install the Sprinklers on the Risers.  Install them the right way and it will massively reduce the need for future repairs.

That’s a lot of pages of information but a lot of it is checklists and diagrams that you will just skim over quickly, so don’t get discouraged!  Better to spend 15 minutes reading the tips here than an hour installing it wrong, and two more hours removing and redoing it!

This page leads you step-by-step through the backfill and flush process.  Quick summary:

1. Backfill trenches 1/2 full. Do NOT install sprinklers yet.
2. Flush entire system for 5 minutes with all valves open.
3. Cap all sprinkler risers leaving only one open and flush for 2 minutes.  Cap the riser after flushing and repeat with the next riser, flushing the remaining risers for 1 minute each.  Repeat for each riser until all are flushed.
4. Finish backfilling trenches, don’t backfill around the risers.

Continue reading Backfill Trenches and Flush Pipes →

The first step in physically installing your sprinkler system is to layout, or “stake”, your new irrigation system on the ground.  Start by marking each of the sprinkler head locations in the irrigated area, using your sprinkler system plan as a guide.  (Don’t have a plan?  Stop here.  Don’t make trouble for yourself.  You NEED a plan!)

Place a stake, a flag (they sell flags for this purpose at irrigation supply outlets), a long nail with a ribbon tied to it, or whatever, at the location of each sprinkler head.  (At this point I suggest you NOT use paint as a sprinkler location marker, you may need to make adjustments and paint makes that difficult.)  Now carefully double check the distances between each of the sprinkler heads. You don’t want to find out that the sprinklers are in the wrong place after they are buried in the ground! Measure the distance from each sprinkler head to the next head in each direction. If your system is properly designed there should be at least 2 other sprinklers (usually 3) about the same distance away. Make sure that none of these distances are more than the maximum spacing allowed for that sprinkler head model. (See the Sprinkler Design Tutorial for more information on maximum sprinkler spacings.)

Rule of thumb spacing guidelines:

• If the distance between spray type sprinklers is more than 18′ there’s a problem.
• If the distance between rotary nozzle type sprinklers is more than 35′ there’s a problem.
• If the distance between rotor type sprinklers is more than 35′ there’s a problem.
• If the distance between any 3 adjacent heads varies more than 20% there is a problem.
• If you don’t know what spray, rotary nozzle, and rotor type sprinklers are read the article on Types of Sprinklers.

The spacings shown above are maximums! The best spacing is probably less than these distances! Remember, the water from one sprinkler should spray all the way to the adjacent sprinkler. Sprinklers are designed to require 100% overlap. You will have dry spots without that required overlap. (This is not greed on the sprinkler manufacturer’s part, there is a scientific, mathematical reason for this overlap.  See the article on Sprinkler Spacing for details. )

If the sprinklers are too far apart you will need to adjust the sprinkler locations, another solution is to adjust the perimeter of the area to be watered to make it smaller, or redesign the system. Never stretch the spacings between sprinkler heads beyond the maximums, you will get very noticeable dry spots! Remember that it is easier and cheaper to redesign everything at this point than it will be to fix problems later!  Adding more sprinkler heads to a system later in an attempt to get rid of dry spots generally does not work out well, is a lot of work, much more expensive, and almost always just creates new problems.  (Right now it may seem like you need to rush to get this sprinkler system in the ground, but waiting a few weeks to fix the problems is nothing compared to the grief of living for years with a horrible sprinkler system that doesn’t work.  Many, many regretful owners of bad sprinkler system have told me that this is advice they wish they had heeded.)

Now you need to mark the pipe locations on the ground. You can use chalk, white paint, or just drag a shovel over the ground to mark where the trenches will be.

For do-it yourselfers I recommend that you mock-up the pipes at this point. Lay the pipes on the ground (don’t cut it yet, just use full lengths to get a feel for the layout) and then lay the fittings next to the pipe at the locations of the sprinkler heads, drain valves, junctions (tees), and bends (ells.) This will help you visualize how the whole thing will fit together and will identify any missing fittings you need to buy.  Don’t mock up fittings and pipe by actually fitting them together, they are extremely difficult to get apart. Just lay them next to each other on the ground.  If you plan to use swing risers for the sprinkler heads you can preassemble them at this time, and screw them into the tee or ell that will be attached to the lateral pipe. This will save time later as it is easier to screw them into the fittings before the pipe or tube is assembled.

Don’t attach the sprinklers yet. After you have everything laid out, get a bunch of plastic bags. Place the fittings along with the sprinklers and risers for each location together in a bag and label it. I use small plastic trash bags. Then I write a number on the bag and write the same number on my irrigation plan at the location where the fittings in the bag go. Now I won’t have to search for the correct fittings later when I’m hot and tired.  A little preparation now saves lots of time and frustration later! Be sure to move the pipe out of the way when you’re finished so you don’t break it when digging trenches or pulling tube.

Next, mock-up the valve assemblies to make sure you have all the proper parts you will need for them. Make sure the manifolds will fit into the space allotted. I actually do the final assembly of most of the valve manifolds at this point and set them aside. If the manifold is made of metal pipe and will be connected to another metal pipe in the field, I use a special fitting called a “union” at the point where the two sections will connect. The union allows the preassembled manifold to be installed much quicker and easier. If you’re not familiar with unions ask your supplier to show you how they work. They aren’t cheap but they are worth every penny you pay.

Make sure you follow the instructions for making leak-free threaded joints. Now, when your ready to install the manifolds later, just grab the preassembled manifold and slap it into place. I like to assemble the manifolds in my garage where its cleaner, cooler, and I have a vise to hold the pipe while I thread it together. Warning: if you use a vise never squeeze PVC pipe to the point that it’s shape deforms! You may create invisible hairline fractures that will begin to leak in a few months.

One last tip. When you dig the trenches or pull the tube into the ground, all the sprinkler head markers (flags or stakes) will get moved. So here’s a trick to help you find the locations again later. For each sprinkler head get a 20 foot long piece of string and two large nails about 4″ long. Tie the string around the sprinkler flag so that the flag is in the middle of the length of string. Now tie a nail to each end of the string.  With the flag at the sprinkler head location, stretch out the string tight to form a V with the nails about 5 feet apart from each other and shove the nails into the ground. Now you can move the flag and dig the trenches. Don’t pull the nails out! To find the sprinkler location again just stretch the string back out tight from the nail locations to create the V again. The flag will be at the same location it was before!

This article is part of the Sprinkler Irrigation Installation Tutorial Series
<<< Previous Page ||| Tutorial Index ||| Next Page >>>
By using this tutorial you agree to be bound by the conditions and limitations listed on the Terms of Use page.

The right tools make the job a whole lot easier and are worth investing in!  Twenty or even forty bucks for a good tool is a lot cheaper than 3 weeks laid up in bed with a pulled muscle.  Most tools last a long time.  Also consider renting or borrowing tools if you are on a budget.

The tools required to install an irrigation system are pretty basic; a shovel, hacksaw, wire cutter, a couple of wrenches, and a knife will get the job done in most cases. But a few special tools make the work much easier and faster to perform. Here is a list of the tools commonly used by professionals.

Continue reading Irrigation Tools →

Automatic fertilizer injectors are the popular gimmick of the moment.  I really don’t find them all that convenient, it seems just as easy to spray fertilizer with a sprayer and be able to put it where I want it as it is to calibrate the fertilizer injector.  With that said, it seems everyone wants a fertilizer injector lately for some reason.

I’m not a huge fan of fertilizer injectors, especially for sprinkler systems.  For drip systems it makes more sense, as the fertilizer water is not sprayed into the air.  I think fertilizer injectors are excellent for agricultural crops, but not nearly as well suited for home landscapes.  A few of the issues:
1. First is control, the fertilizer gets applied at the same rate to everything.  Different plants need different amounts of fertilizer.
2. Second is uniformity, if the fertilizer isn’t evenly mixed into the water you can get burning of foliage.  The maker of the fertilizer injector will have recommendations for addressing this issue.  Generally it just means you need to have several feet of pipe between the injector and the first sprinkler head or drip emitter.
3. Third is health, most sprinklers produce mist which drifts easily to adjacent property.  Without care it can contaminate or cause sickness.  The EPA has strict rules regulating maximum wind speed that can occur during chemical applications using aerial spray nozzles.  Generally what this boils down to is that the fertilizer injection should be manually controlled and only used when someone is supervising the system.
4. Backflow prevention- because the fertilizers are chemical injection (high hazard) a reduced pressure backflow preventer is technically the only type of backflow preventer that is satisfactory.  They are very expensive and few homeowners have them.  Talk to your water provider about the specific requirements for your area.
5. Runoff- most residential sprinkler systems have substantial runoff.  With fertilizer in the water this can cause environmental problems with storm-water drainage disposal.  This high nutrient content runoff water causes algae blooms in lakes and estuaries, and also encourages growth of non-native weed species along streams and rivers.
6. If the fertilizer sprays onto a car it must be washed off immediately.  If it drifts onto your neighbors car and sits all night the fertilizer can damage the paint.
7. Nitrogen, the primary nutrient you will be applying,  is easily volatilized (evaporated) into the air.  This means that when you spray fertilizer as a liquid into the air you loose some of the nitrogen.  Two factors heavily influence this.  Volatilization is a much greater problem with warmer temperatures and it also increases if the water droplets are smaller.

If you can address all the above issues, then it is a great thing.  In agricultural situations with a single crop and strict supervision this is efficient and easy.  Homeowners tend to be looking at fertilizer injectors as a “set it and forget it” solution.  It is not.  It requires much more work than either broadcast or hand applied foliar fertilization methods.  Very few commercial landscapers use injectors, high costs and labor requirements for supervision, combined with liability exposure for poisoning pets and people are the reason.

I prefer hand applied foliar treatments where the level of control is much higher.  Only the plants that need more fertilizer get it.  I am a big fan of foliar applied fertilizer using a sprayer.  It is much more efficient than broadcast fertilizer, works faster, and typically results in less environmental pollution.

The best tip I have for hiring a contractor is for you to provide the plan and have them bid on it as designed.  That gives you the quality you want plus it allows for accurate comparison of prices between contractors.  It’s a bit of work, but I strongly suggest that  it is worth the effort.  Most contractors are not the greatest designers, lots of them write to me about the website, glad they found it so they can feel more secure about their designs!

If you don’t design it yourself (or have it designed) then I suggest putting together a list of requirements for the contractors, such as:

Head to head coverage
No 1/2″ pipe
No flows over 7 feet/second
List all products to be used
Manual flow controls on all valves.
Maximum spray head spacing of 17 feet.
Maximum rotor spacing of 35 feet.
No spray on sidewalks or streets (except wind drift).
Pipe at least 10″ deep.
Pressurized mainlines at least 18″ deep.
Filter (100 mesh screen) on mainline supply.
One year written warranty on parts and labor.
If poly piping, all fittings clamped.
Wire splices watertight.

Be clear up front with the contractor in what you want as a result.   Don’t tell the contractor how to install the system (you could be liable if something goes wrong), tell them what result you want to see.  Leave the “how to” up to the contractor, you tell him what you want to see as a finished result.    Here’s an example of being specific:  If you want the pipes 10″ deep, specify that you want the top of the pipe 10″ deep, not the trench 10″ deep (with a 10″ deep trench much of the pipe will be 8″ deep due to various factors such as dirt that falls into the trench.)  Installing the pipes in shallow trenches saves lots of time and money for the contractor.  It also significantly increases the chance you will accidentally break a pipe.

Be sure to ask for results that have a clear definition.  For example, “full coverage” is a popular term with contractors but it is also a non-defined term, what exactly does it mean?  I don’t know and I’m an expert!  If you want good coverage without any dry spots ask for “head-to-head” coverage or “100% overlap of sprinklers” (they both mean the same thing.)  If the contractor says he will give you full coverage, or no dry spots that is very easy to deliver.  If there is a dry spot the contractor will just increase the watering time so that the water from adjacent areas floods into the dry spot.  That is not a good solution, it just wastes lots of water.

It doesn’t take a whole lot of capital to get into the sprinkler installation business.  Unfortunately this means a lot of landscape contractors are seriously under capitalized.  They go out of business at a very high rate.  You can’t always tell who’s in trouble either.  I hired a contractor who had been in business for decades in the same location and had several stores.  A week later he packed up and fled the country, taking with him all the remaining company assets, leaving all his jobs unfinished, and taking thousands of dollars of deposits with him.  So you need to take steps up front to protect yourself.  In particular if you are in the USA you need to understand the lien system and how our laws work when it comes to home improvements such as a sprinkler system.  You must be extremely careful!

Payments:
This is general information, your actual situation may call for higher or lower values.

You should not put more than 10% down prior to start of work.  In California the law prohibits down payments to contractors that exceed 10% of the total job cost.  Some other states have similar laws.  But even if they don’t, protect yourself.

Generally you can make a payment of up to 40% when all materials are delivered and you have them in your possession.  The materials are usually valued at about half of the total cost of a installed irrigation system.

The remaining payment should not be made until the contractor is finished.

READ THIS!  This applies to the USA and may apply in other countries.
Get a signed lien release from the contractor before making any payments over 50% of the total cost.  It is critical to get a release of lien from the contractor to protect your house value.  The law allows the person who sold the contractor the sprinkler materials to file a lien on your house and collect from YOU if the contractor doesn’t pay his bill.  They can still collect from you EVEN IF YOU ALREADY PAID THE CONTRACTOR!  You can be made to pay twice!  That is the law.  As soon as building materials are delivered to your property they are considered to be part of your property.  By law, the supplier can’t repossess building materials, they become part of the property as soon as they are delivered.  So the law protects the supplier by allowing the supplier to place a lien on your home for the value of the materials.  The supplier can then force the sale of your home to pay the lien.  You MUST protect yourself against this by having the contractor provide you with a lien release prior to final payment.  A lien release just says that in exchange for payment the contractor will not allow a lien to be attached to your home.  Standardized lien release forms are available at many office supply stores.

Many smaller contractors don’t have a clue about liens or how to make a lien release, especially if they are not licensed. If you are dealing with a small contractor such as this I recommend you obtain the contractor’s material list and purchase the materials yourself from the supplier.  Then have the supplier deliver the materials directly to your house.  This avoids the problem of liens by the supplier.

You can’t fully protect yourself from bad contractors.  Most of my projects are competitively bid, so I have no control over who is selected to do the installation.  I often have to work with bad contractors, and a good number of them have gone bankrupt on my projects.  What do I do?  First, I watch them.  I check to be sure that they are giving me what I ordered.  What about the ones who walk off the job or go bankrupt?  That’s why you don’t pay them everything up front.  Always hold back at least 10% of their money until you are completely happy with the job.  If they do go belly up and take some of your money with them you may have some protection.  If they are a licensed contractor most states require that they have a “bond”.  Contact the state license organization and find out the name of their bond company.  Then contact the bond company and file a claim against their bond.  Don’t wait around to do this, file a claim ASAP as most bond companies pay claims “first come, first served” and once the money runs out you are out of luck.  Last results is the court system, but don’t expect much.  You can’t get any money from them if they don’t have any.

Finally, educate yourself.  Read through the Sprinkler System Design and Irrigation System Installation tutorials on my website.  Take notes.  Yes it will take some time.   But even simply reading them will teach you a lot and greatly reduce the chance you will get a bad sprinkler system.

Throughout my tutorials and articles on irrigation system design I recommend against the use of double check type backflow preventers on irrigation systems connected to potable water supplies (drinking water).  This article is an explanation of why.

A double check backflow preventer is simply two spring-loaded check valves in a row, with a shut-off valve on either end and test cocks to allow the unit to be tested for proper operation. The double check backflow preventer is the only true backflow preventer which does not have a vent to allow air to enter the lines or to allow water to escape when backflow occurs. It relies entirely on the tight seal of the two check valves to prevent backflow.  While it may come as a surprise, the experts who regulate backflow preventers consider the lack of a vent to be a major problem, and thus they consider double check backflow preventers as appropriate only for low-hazard situations.  More on this below.

So why can’t a double check backflow preventer be used with water containing hazardous substances? The answer is really pretty simple. Two check valves sounds like good protection, after all if one fails there is a backup, right? The problem is found in the cause of the check valve failure. They almost always fail because something gets stuck in them (sand, twigs, insects, clams) which prevents them from closing. Unfortunately, where there is one of those contaminants, there are often many! Thus while the chances of one check valve failing may be fairly low, the chance that the other check valve will fail at exactly the same time is very high. That is the reason why double checks can’t be used when hazardous substances may be present in the water.

Irrigation water is considered by many experts to be hazardous, this is especially true of the agencies that regulate health and safety laws.  The reasoning is that dangerous chemicals (fertilizers, pesticides) as well as soil borne contaminates (animal excretions, decomposition) are found in irrigated areas and these substances may be drawn back into the irrigation water through the sprinklers or drip emitters when backflow occurs.  This is especially likely if water ponds on the ground around a sprinkler head or emitter.

Pro Double Check Backflow Preventer Argument:
The double check backflow preventer is less susceptible to freezing damage because in most cases it can be installed below ground or inside a basement. This makes winterization of the irrigation system much easier. Supporters of double check backflow preventers also argue that irrigation water is not a hazard to health, it is merely objectionable (tastes bad, looks bad, or smells bad, but won’t make you sick). This point is essential, because pretty much all authorities agree that double check backflow preventers are not appropriate for use when health hazard substances are present in the water. The final argument often used in favor of double check backflow preventers is their lower cost to purchase.

Anti Double Check Backflow Preventer Argument:
The con argument is really simple, they claim that irrigation water is hazardous to your health, and thus a double check backflow preventer is not suitable. The argument goes something like this– whenever an irrigation cycle is completed, gravity causes at least some of the water in the pipes to run out onto the ground through the lowest sprinkler head or drip emitter (even if they are only an inch lower). When the water runs out a vacuum is created in the pipe. This vacuum sucks stuff from the ground into the pipe through the higher sprinkler heads or emitters. That includes stagnant water, dirt, fertilizer, bacteria, animal waste, and anything else present at ground level. All of those can be hazardous to your health. Once in the pipe they can then flow back into the water supply. So irrigation water is a health hazard.

What the organizations involved in the backflow industry say about double checks:

The AWWA (American Water Works Association) is an organization consisting of people interested in issues related to water. Most members are people who work for public or private water companies or who work for companies that make water related products (like the backflow preventer manufacturers). The AWWA publishes consensus standards which are created by committees made up of various Association members who debate and attempt to reach a consensus on what should be in the standard. To put it another way, these standards are based on the collective opinions of the committee members rather than on research or other factual data. This is not bad, but it is important to recognize that these standards are the result of a political, rather than scientific, process. The position of the AWWA on double checks is stated in standard “C510-92 Double Check Valve Backflow Prevention Assembly”. This standard says that double checks may be used for sprinkler irrigation systems, provided no chemicals are injected into the sprinkler water.

The Foundation for Cross-Connection Control and Hydraulic Research at the University of Southern California creates a set of standards which it publishes as the “Manual of Cross-Connection Control”. The Foundation also tests various makes and models of backflow preventers for compliance with the USC standards and gives approvals to those that meet the standards. The foundation is an independent organization that bases it’s decisions and standards on research data. The backflow preventers that pass the Foundation’s minimum standards and tests are listed in the official “List of Approved Backflow Prevention Assemblies”. USC rates undesirable water into 3 classifications; Pollutants (non-health hazard), Contaminants (minor health hazard), and Lethal Hazard (sewage or radiation present). The position of the Foundation on double checks is that “The DC may be used to protect against a pollutant only”. So is irrigation water a pollutant or contaminant? Back to that same old question…

My recommendation:

I do not recommend the use of double check backflow preventers on irrigation systems. I do not use double check backflow preventers on my projects except in very rare cases where I am either required to, or special conditions exist such as sprinklers mounted very high above the ground where contaminates can’t reach them. There is a very simple reason for this. I am a registered Landscape Architect, and as such I am required above all else to “protect the health, safety, and welfare of the public”. Thus I am held to a higher standard than a homeowner or other non-licensed person and my advise must reflect that. So if you write and ask me if I would recommend using a double check, even if you think you have a special circumstance that eliminates almost ALL of the risk, I am still likely to tell you no. Because that is what I have to tell you!

Your decision?
So, should YOU use a double check backflow preventer? Well, that is, of course, up to you. If you have a local regulating agency who says you MUST use a double check backflow preventer then you don’t have much choice. The good news is that I haven’t heard of any cases of anyone killed or disabled as a result of backflow from an irrigation system, as long as the irrigation system had some type of backflow preventer on it.

A final note:
I’ve taken a lot of heat from people over my position on Double Check Backflow Preventers. I’m rather tired of being flamed for it, it’s my opinion and that’s all. If you have a correction or addition to the arguments above I would love to hear it, and in most cases I will incorporate it into the arguments. If you simply disagree with my recommendation, that is fine, I don’t mind at all, but I don’t want to hear about it. I’ve tried to give my readers as fair as possible a view of both sides of the issue so that they can make a decision. I hope that I have accomplished that.

Here are some pressure loss tables you can use to calculate the friction loss in your house or irrigation system mainline.  This is the old-school, low-tech method.  There are also free spreadsheets available (they use the free Open-Office spreadsheet program) on this website that will calculate pressure loss for you.  The spreadsheets cover more types and sizes of pipe than these tables.  I suggest using the spreadsheets, but these tables are handy if you want to do a quick look-up of a value, or just don’t do spreadsheets.

Quick background for those who linked to this page from a search for water pressure or something similar.  As water flows through a pipe it losses pressure.  The pressure is lost due to friction of the water against the pipe walls and also turbulence as the water tumbles around.  Knowing how much pressure loss to expect is important.  If there isn’t enough pressure left at the end of the pipe, then things like sprinklers, washing machines, dishwashers, faucets, toilets, etc. will not work.  For very general purposes, most of the fore-mentioned items need at least 20 PSI of pressure to operate.  Most will work much better at 30 PSI.

How To Use a Pipe Pressure Loss Table:

(PSI = pounds per square inch = lbs./sq.in.)

• Select the proper table for the type of pipe, i.e.; SCH 40 PVC, SCH 40 steel, polyethylene, copper, etc.
• Locate the proper column on the table for the pipe size.
• Read down the column to the row for the flow rate (GPM) in the pipe section. You will find a PSI loss value (given as PSI/100).
• Multiply the PSI loss value shown by the total length of the pipe section, then divide the product by 100. (PSI loss on these tables is given in PSI per 100 feet of pipe.)
• Pressure loss values highlighted in yellow italics are over 5 feet per second. This is a high velocity, but considered acceptable for short distances (less than 50 feet of pipe length.)
• Pressure losses greater than those shown on the chart can cause permanent and expensive damage to your plumbing. You must use a lower flow (GPM) in the pipe.

PSI Loss Value x Length of Pipe / 100 = PSI loss in pipe

Example: 1″ size, type SCH 40 PVC mainline. The length of the mainline pipe is 23 feet. The water flow rate through the mainline is 18 GPM. Using a pipe pressure loss table we find that the PSI loss for 1″ SCH 40 PVC at a flow rate of 18 GPM is 8.12 PSI per 100′. Therefore:   8.12 x 23 / 100 = 1.87 PSI – to simplify, you can round up the value to 2 PSI loss

(Note: PSI loss charts vary somewhat from each other. Other charts may result in an answer slightly different from the one in this example.)

PRESSURE LOSS TABLE FOR SCH 40 PVC PIPE

Pressure losses highlighted in yellow italics reflect flow velocity between 5 and 7 feet/second. Use care utilizing flow velocities in this range. Water hammer damage can result from a combination of high pressure and high velocity. Pressure losses shown are in PSI per 100 feet of pipe length.

PRESSURE LOSS TABLE, POLYETHYLENE PIPE

For SDR-7,  SDR-9,  SDR 11.5,  and SDR 15  (all have the same inside diameter)

Pressure losses highlighted in yellow italics reflect flow velocity between 5 and 7 feet/second. Use care utilizing flow velocities in this range. Water hammer damage can result from a combination of high pressure and high velocity. Pressure losses shown are in PSI per 100 feet of pipe length.

Pressure Loss Table, Type K Copper Pipe or Tubing

Type K copper pipe has the thickest wall and highest pressure ratings of the common copper tubing types. In order of wall thickness, common copper tubing types are Type M (thinnest), Type L, and Type K (thickest). Type L is commonly used for household plumbing. Type K is most often used to make short threaded-end nipples.  If you don’t know what Type the pipe is, assume it is Type K.

Pressure losses highlighted in yellow italics reflect flow velocity between 5 and 7 feet/second. Use care utilizing flow velocities in this range. Water hammer damage can result from a combination of high pressure and high velocity. Pressure losses shown are in PSI per 100 feet of pipe length.

PRESSURE LOSS TABLE, TYPE L COPPER PIPE OR TUBING

Type L copper tube is the type most commonly used for household plumbing. In order of wall thickness, common copper tubing types are Type M (thinnest), Type L, and Type K (thickest). If you don’t know what Type the pipe is, assume it is Type K.

Pressure losses highlighted in yellow italics reflect flow velocity between 5 and 7 feet/second. Use care utilizing flow velocities in this range. Water hammer damage can result from a combination of high pressure and high velocity. Pressure losses shown are in PSI per 100 feet of pipe length.

Q.  I was wondering if the size of the water pipe makes a difference in the performance of the sprinkler head — 3/4 inch or 1 inch ??    I have the option of supplying my sprinklers with either a 3/4 inch or a 1 inch water supply line.

A. Yes, the pipe size does make a difference.  The industry “rule of thumb” is that the pipe should never be smaller than the sprinkler inlet, although there is no technical reason for that.  There could be situations where a smaller pipe will work just fine.  But they are not common.  The truth is that in most cases the appropriate pipe size is one to two pipe sizes larger than the inlet.  I’ve seen some sprinkler systems where the pipe needed to be several times larger than the sprinkler inlet, although those situation are very rare.  To confuse things more, some sprinklers have two different size inlets.  In the case of two inlet sizes I would typically use a pipe the same size or LARGER than the largest inlet.

The Right Way:

Risky but Expensive Simple Solution that Usually Works:

If you really don’t want to deal with looking stuff up and doing calculations, one solid rule in irrigation design is that a pipe can never be “too large”.  (For a detailed discussion of why, see why a smaller pipe will not increase pressure.)  So if you are in doubt, you always use a larger pipe size.   You could hook up a 1/2″ sprinkler to a 10″ pipe and the sprinkler would work just fine.  The 10″ pipe would not be kind to your budget, however.

You can use this “larger is never worse” rule to your advantage.  If you really don’t want to deal with calculating the right size, one way to solve the problem is to use a ridiculously over-size pipe.  Ie; if the sprinkler has a 1″ inlet use a 1.5″ pipe  and you will probably be safe.  Of course this may well be overkill as well, but if you don’t want to do all the calculations, then you pay the price of a larger pipe and go with over-kill.  Remember you do this solely at your own risk!

Pre-filters are used when pumping water from a pond, or a slow moving stream or river.  These instructions are based on a 20 GPM water supply, if you need more water you will need to use a larger pipe and hole, or manifold multiple pipes together. This is a very basic outline of what is required, you will obviously need to adapt it to your situation.

Dig a 3 foot deep 10 foot long hole in the stream or pond bed .  Next make a intake manifold, it is just a piece of 2″ SCH 40 PVC pipe with a cap on one end and your intake pipe connected to the other end.  You then drill one hundred each, 3/8″ diameter holes in the manifold pipe to allow the water to flow into the manifold.  Put a plastic liner on the bottom of your hole.  Now put 6″ of 3/4″ diameter gravel in the hole.  Then lay the intake manifold in the hole on the gravel and pack another 12″ deep layer of 3/4″ gravel around and over it. On top of that you place another 18″ deep layer of 3/8″ gravel.

The gravel acts as a “pre-filter”.  As the water moves slowly down through the gravel layers to the intake manifold the sand and much of the algae gets trapped in the gravel.  This is generally enough to protect the pump.  You still need a filter after the pump and it still might need to have a auto-flush mechanism.

To slow down a fast moving small creek to allow pumping water from it the classic method is to create a small, low, dam using sand bags.  Not only is the use of sand bags easy, it is also temporary and the sand bags can be removed seasonally if desired.

Remember that in most countries there are lots of rules and regulations that apply to disturbing stream beds.  In the USA, at a minimum, you should contact the US Fish and Game Department and EPA for advise.  There are probably also State and Local regulations as well.  The fines for violating rules or regulations can be very extreme!  Make sure you get a ll required permits.