How to Trench and Install Pipe
After measuring and planning for the irrigation system, learn how to dig trenches and install pipes.
Have the utility company mark the location of buried cables in the yard. Calculate the size of the yard with a tape measure. Measure the water pressure and determine the sprinklers’ coverage. Make a diagram on paper and plot the types and locations of the sprinkler heads. Mark the yard with flags where the sprinklers will go.
It's important to have the spray from one sprinkler head make contact with the other heads to ensure there will be no dry spots in the yard.
The easiest way to provide water for an irrigation system is to connect to an existing spigot. The more professional way involves tapping into the main water-service line. Both ways require the installation of an anti-siphon valve, which prevents brackish water, lawn chemicals and fertilizers from entering the main water supply.
Dig a trench 6" to 8" deep with sides sloping at a 45-degree angle. When digging, place sod to one side and soil to other to make filling and patching the trench easier. Rent a trenching device, also called a vibratory plow, to make this stage go much faster.
Dig a hole slightly larger than the valve manifold box. Place the box in the ground. Attach one end of the valve manifold assembly to the main water supply line. Tighten the clamps to secure it.
Connect 3/4" PVC pipe to the open end of the valve manifold. Continue laying the pipe along the main trench. Use “tee" connectors for pipes running off the main line. At the location of each flag, attach risers using 90-degree connectors. When gluing sections together, be sure to apply the adhesive thinly and smoothly.
Select the appropriate sprinkler heads based on the irrigation needs of the lawn and landscape. Before attaching sprinkler heads, flush water through the system to clean out any debris. Install the sprinkler heads onto the risers. Level the sprinkler heads with the soil level. Fill in trenches and holes with dirt and sod.
The timer controls the length and frequency of waterings. Connect the wires according to the manufacturer’s specifications. Make final connection to main water-service line. Check to see if system is working. Fine-tune all sprinkler heads to ensure even coverage.