How to install a lawn sprinkler system

install a lawn sprinkler system

With a spade, dig up the sod and place the strips aside. Then dig a V-shaped trench to a depth of 6 to 10 inches, sloping it away from the house 1 inch for every 8 feet. To gauge the slope, slip a 1/2 inch spacer between a 4-foot level and a straight 2×4 that is at least 4 feet long. When the bubble in the level is centered, you have the right shape.

Tap into the supply line indoors with 3/4 inch PVC pipe. Drill an exit hole through the wall with a masonry bit at the level of the trench. Attach the vacuum breaker to the control valve. Generally the pressure breaker must be at least 8 inches above the highest sprinkler head, but check your local building code.

Run pipe from the control valve by solvent-welding or using adapters.

Lay 3/4 inch pipe in the trench. For straight runs, use PVC pipe and fittings secured with solvent cement; for curves, use PE pipe, barbed fittings, and band clamps.

Insert 3/4×1/2 reducing Ts for the sprinkler heads 7 to 10 feet apart, depending on soil, head coverage, and plant type.

Connect the heads to the Ts following the manufacturer’s instructions so the heads are flush with the top of the trench. These pipes have 1/2 inch male pipe threads on both ends. The upper end can be snapped off at whatever height you need. Attach the risers in the T according to the manufacturer’s instructions.

Spread gravel under the piping at any low points along its length to maintain the slope. At the end of each line, attach an automatic drain valve to an adaptor and a short piece of pipe. This will drain water after the system has been turned off.

Turn on the water and test the system, checking that all the heads pop up and there are no leaks. If there are leaks, tighten the band clamps. If the leak is at the fitting, cut it out and replace it. Then backfill the trench and fit sod around the heads with a garden tool.

Unless you’ve opted for a manual system, you’ll need to wire the control box to the control valves. For indoor models, run the wires to a convenient location in the house and make the connection according to the manufacturer’s instructions.

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