To install an underground sprinkler system, draw a map of the intended layout, avoiding areas that contain underground utilities, and place stakes and string them along the desired sprinkler lines. Dig trenches that are 6 to 12 inches deep, and install the water supply lines. Connect the sprinkler heads to the pipe according to the manufacturer instructions, connect the system to the water supply, and install a backflow prevention device.
Before beginning, refer to local regulations to determine whether a building permit is necessary and to determine what type of backflow prevention device to install. When planning the installation, create zones on the property, and install enough sprinkler heads in each zone to allow the water to slightly overlap when the sprinkler heads are on.
Set the sod aside when digging the trenches, and use the sod to cover the trenches after installation of the system. Check the trenches to ensure they are level before installing the system.
Before connecting the PVC pipe with adhesive, dry fit the lines to ensure they fit together properly, and then connect the lines. Install the control panel as instructed in the owner's manual, turn the system on to check for leaks, and set the timer.