A properly installed and maintained underground sprinkler system conserves water by directing it exactly where and when it's needed.
Living landscapes need water to survive and flourish. Relying completely on natural rainfall sometimes isn't the best method of supplying water. Depending on the type of grass and other plantings you have in your landscape, a more constant source of water may be required and a home irrigation system might be what you need.
Installing your own home irrigation system can save you money. However, it's not one of the easiest do-it-yourself projects around. Planning and purchasing the correct components are the keys to success. Keep in mind that putting in an irrigation system isn't your typical Saturday morning project. Installing a system usually takes more than one weekend to fit and fine tune.
But don't be discouraged. Most manufacturers of home irrigation systems have design and planning guides that simplify the job considerably. Check this resource and then decide whether to do it yourself or hire a pro. Use our online system planner.
First, decide if you really need an underground irrigation system. The type of grass in your lawn affects irrigation needs. Some turfgrass varieties have higher water requirements than others. Your soil type also affects the efficiency of irrigation as well. Sandy soils absorb water more quickly than clay soils. If you supply more water than the soil can absorb, runoff is the result. An irrigation system gives you better control of the moisture content of your soil.
Before installing a permanent irrigation system, you'll need to:
In order to purchase the right components, you'll also have to determine your own specific:
Before beginning any excavation, call 811 to check for underground utilities.
There are two measurements of water pressure, working (when the water supply is turned on) and static (when the water supply is shut off). You'll need your working water pressure number.
Checking your water pressure requires a pressure gauge. If you can't borrow one from a plumber buddy, you can buy one. The gauge attaches to the outside faucet and provides a pressure reading in pounds per square inch (psi). Make sure all other water faucets (indoors and out) are turned off when you take the reading.
You can also get your water pressure from your local municipality, but it's likely to be an average for the neighborhood rather than for your home specifically.
Maintaining an improperly installed system can be difficult to say the least, so take the time to plan and install it right from the beginning.
If you're on a municipal water system, you should find the size imprinted on the meter itself. If you can't locate it, look on your utility bill or call your water provider. Water meters are 5/8-inch, 3/4-inch or 1-inch.
If your water comes from a source other than a municipal system, such as a well, you'll need the pump size. Look in the owner's manual or if necessary, contact the manufacturer.
To match the size of irrigation pipe to your existing water service, you'll need to know the size of your incoming supply line. To do so:
1. Get a piece of string.
2. Wrap it once around the water pipe.
3. Measure the length and compare to the chart below.
|String Length||2 3/4-in.||3 1/4-in.||3 1/2-in.||4-in.||4 1/8-in.|
|Copper Pipe||3/4-in.||1-in.||1 1/4-in.|
|PVC Pipe (sch 40)||3/4-in.||1-in.|
Service line size is in italics
Flow rate is measured in gallons per minute:
1. Get a container that has a measurable or known capacity.
2. Turn on the water.
3. Record the time it takes to fill to a measurable level.
4. Divide the filled container size (in gallons) by time (in seconds) it takes to fill it.
5. Multiply it by 60 seconds.
6. The number you get is the flow rate in gallons per minute (GPM). Multiply that number by 60 if you need to determine gallons per hour.
A 3-gallon bucket takes 15 seconds to fill.
3 ÷ 15 = 0.2
0.2 x 60 = 12 GPM or 720 GPH.
A 4-gallon bucket takes 30 seconds to fill.
4 ÷ 30 = 0.130
.13 x 60 = 7.8 GPM or 468 GPH.
Refer to local ordinances for backflow prevention requirements.
When you've completed all of the preliminary research, it's time to start laying out your system. Most yards have a variety of elements that have to be considered when laying out an irrigation system:
Because of these features, you'll most likely have to create more than one watering zone. The number of zones you need also depends on the GPM your system can supply. A zone (or circuit) is an independently contained set of pipe and sprinkler heads. Zones are determined by the physical attributes of your landscape and the capacity of your water supply. Each zone has its own control valve.
A map is essential when establishing watering zones. Begin by measuring and mapping your property to scale on graph paper. A scale of 1 inch = 10 feet is recommended. The map should include the house and all permanent landscape features. Mark on the map where the water meter is located. Use our online system planner.
Landscape features need to be clearly marked so that the installed system will water only areas with living materials and will provide complete coverage for them. Note prevailing winds if you feel they'll affect coverage. More importantly, mark sloping areas in your lawn. If your yard is sloped, the water pressure changes (lower as the elevation increases, higher as it decreases), affecting the amount of water delivered by the sprinkler.
You'll also need to draw where the manifold will be located. The manifold needs to be located in an inconspicuous spot near the water supply line.
Be prepared to make more than one version of the map if necessary. It's much easier to explore alternatives on paper before you begin digging. Keep the final zone map for reference. It will come in handy if future maintenance is required.
When installing a sprinkler system, 100 percent coverage is essential to avoid dry spots. In order to achieve this, overlap the spray pattern. "Head to head" coverage refers to the sprinkler head layout that allows spray from each sprinkler head to reach the adjacent head, ensuring overlap.
Each sprinkler head is designed for a specific watering need. Many are adjustable to allow targeted spot-watering without watering inorganic objects such as sidewalks, driveways or the house.
Select sprinkler heads based on the coverage required. The number of zones and the sprinkler head size and style depend on the location of trees, shrubs, lawn and sidewalks. Large areas need one style, corners need another, and areas under shrubs need still another type. Your irrigation planning guide should have a list of sprinkler head types.
Pop-up style lawn sprinkler heads are installed just below ground level. Set pop-up sprinkler heads so that they will not be damaged by mowers or foot traffic when retracted. The best ones are adjustable. Shrub sprinklers are taller for use in flower and shrub beds. When selecting the proper height to install, keep in mind the mature size of the plants.
Mixing head types in one zone decreases efficiency. Always use the same type of head for each zone.
Done with the planning? Take your water measurements and maps with you when shopping for parts.
You must select your system components to match your water supply and water pressure. A mismatch will either overstress the system or provide insufficient irrigation.
A rain sensor reacts to natural rainfall and shuts off the irrigation system. Some areas require this water-wise component for conserving water.
Polyvinyl chloride (or PVC) pipe is the most common irrigation material. The familiar rigid white material is stronger than polyethylene. Connections are made using adhesive.
The alternative material is polyethylene. Because it's flexible, it's used in colder climates to adapt to extended freeze cycles. Polyethylene comes in rolls and can be curved around natural and manmade obstacles, requiring fewer fittings than PVC. Connections are made with specially designed clamps.
Both types of pipe are cut with a handsaw or pipe cutter.
A machine called a pipe puller is great for installing polyethylene pipe, but requires a little expertise to operate. Unless you want to get some on-the-job training in your front lawn, this machine is perhaps best left to the pros.
The design is done, the parts are selected and you are ready to dig and install. Lay out the location of the lines with stakes and string. Place a flag or other marker where the sprinkler heads will be located.
The trenches required for the system are relatively shallow — 6-12 inches deep depending on the freeze cycles and frost severity in your area. The trench must also be deep enough to allow the sprinklers to retract underground to prevent breakage from lawn machines.
Dig the trench by hand or rent a trencher (a real time saver). If you choose to dig by hand, a garden spade with a square edge is the best tool to use. A ditch spade is also pretty handy for working in a narrow space. It's advisable to hand dig in flower or shrub beds to prevent damage to plants.
The trenches must be level. If some heads are lower than others, gravity will reduce efficiency. Dig only as much as you can install in each work session. Save the sod to re-cover the trench.
Assembly is a snap once all of the pre-planning is complete. Lay out the pieces first. Pre-assemble parts when possible before putting them in the trench. It's best to connect components working outward from the manifold.
Cut the pipe to length with a hacksaw or pipe cutter. Make your cut straight so the pipe will be fully seated in the fitting.
Smooth and bevel the edges slightly with a knife or fine file.
Insert the pipe into the fitting and adjust to the correct position. Mark the pipe and fitting with a reference line to make it easy to find the position again after you have added the cement.
Remove the pipe from the fitting.
Clean the surfaces to be mated with a solvent primer.
Brush both the outside of the pipe and the inside of the fitting with cement.
Push the pipe into the fitting with your reference marks 1/4 turn apart. Twist the pipe to align the marks. This spreads the cement and makes a bead along the edge of the fitting. The bead should extend all the way around the pipe. Work quickly — the adhesive sets in about 30 seconds. If you make a mistake, separate the parts quickly. Once the joint is set, it's stuck for good.
Cut the pipe to length with a pipe cutter or hacksaw.
Place a clamp on each end.
Insert the fitting into the pipe.
Tighten the clamps.
Systems vary by manufacturer, with the heads usually threading onto the riser. Read and follow your individual model's instructions carefully.
It's very important to flush debris from the line before final connection of sprinkler heads. It's difficult to locate blockages after everything is in place. A final flush also allows you to check for leaks in the pipeline.
There are two ways to connect your irrigation system to the water supply.
If you plan on connecting your system directly to the service line, you may want to hire a professional to do the work.
Most municipalities require installation of backflow preventers on irrigation systems. Backflow can be caused by:
Backflow can allow chemicals from the lawn to enter the water supply and cause serious problems. A backflow prevention mechanism closes the system when not in use. Make sure it's installed properly. Always read and follow the manufacturer's instructions.
Each zone will have its own controlling valve (only one valve per zone). For future maintenance and repair, note which valve is for which zone.
The manifold groups the valves in one area and allows all zones to be routed through one control. You will be able to run one zone at a time to maximize water pressure.
The timer controls which zone is being watered. Choose timers based on the number of zones you have. Keep a copy of the timer/zone assignments (much as you would keep a reference of electrical circuits in a breaker box). Timers can be programmed to run for a specified time and shut off automatically. A rain/moisture sensor feature is available to detect water levels and shut on and off when needed — a great way to water when you're away from home. Some areas require these sensors as part of an irrigation system.
Always conserve water whenever you can. Timers are a great tool for this, as are temperature sensors. The timers will regulate how much water goes out, and the temperature sensors can tell the system when water is most needed, reducing the amount of wasted water.