How to Lay Out a Lawn Sprinkler System

Sketch the layout of your lawn on graph paper so you design the sprinkler system accordingly. Include the location of buildings and hardscaping that do not need irrigation. Mark the locations of utility lines on the ground with powdered chalk and note them on the sketch.

Determine the water pressure and flow available on your main water supply using a pressure gauge. Ideally, you need 20 to 35 psi (pounds per square inch) and 11 to 13 gpm (gallons per minute) of flow rate to install sprinklers. To measure the flow rate, place a 1-gallon bucket under the bib and determine how many seconds it takes to fill it. Divide the seconds 60 to calculate the gpm capacity for your line. The results help determine the size of each sprinkler's circuit.

Mark the locations of sprinkler heads on the sketch. Multiply the throw distance of the desired sprinkler heads by 1.4 to calculate the spacing in between, so they overlap. Using the diagram as a guide, determine the number of full-circle, half circle and part circle sprinkler systems you need that provide uniform coverage over the area.

Tap into your main water line in your basement or garage and install the manifold and controller to it. Drill a hole through the masonry and install a shutoff valve and stop-and-waste valve that help drain the system for the winter. Also install anti-siphon valves to the control valves to prevent contaminated water from re-entering the main supply line.

Lay out lines for the system along your lawn using string and stakes. Dig 4- to 12-inch-deep trenches over the lines for the pipe that will carry water to the sprinkler heads. Lay the pipes in the trenches and begin making connections. Rub emery paper over the inner and outer corners of each pipe to remove the gloss, and apply a PVC solvent that connects pipes together. Turn the pipes lightly so the solvent takes hold.

Cut riser tees to the correct heights so the sprinkler heads they support lie flush with the ground. Install the tees at the pre-determined spots for the sprinkler heads, and attach the heads to the tees.

Replace the soil in the trenches to cover the pipes. Tamp the soil and replace sod or reseed.