Avoid damage to your in-ground sprinkler system by making sure it is winterized to prevent freezing. Winterizing involves removing water from the pipes and insulating the valves and pump. Complete winterizing of your sprinkler system before temperatures dip to freezing to lower maintenance and repair costs in the next year. Make sure all sections of the system are drained or else water will collect and cause damage.
Turn off the automatic timer for the sprinkler system. The timer is in the controller unit and should be set to "Off" mode. The controller can be shut down completely, but all programming information will be lost for the next year. Shutting down the controller may also increase the moisture level in the unit.
Turn off the water supply at the main shutoff valve. Wrap the main shutoff valve with insulation and protect with a plastic bag. Insulate any pipes that are above ground by applying foam insulating tubes and tape.
Drain and remove the pump from the system if it is located outside. Insulate the pump unit if it cannot be removed.
Drain water from the valves and pipes to prevent freezing and a pipe burst. Hire an installation company to drain the pipes, or do it yourself. The most efficient process is doing a compressed-air blowout.
Attach the air compressor hose to the sprinkler fitting, making sure the pipe drain is open. Open the air compressor valve slowly to introduce air into the pipes. Keep the air pressure at a constant level of 40 to 80 PSI. The sprinkler heads should pop up and seal. If they do not, slowly increase the air until they do. Never exceed an air pressure of 80 PSI.
Complete the blowout process with each sprinkler section.
Insulate any above-ground backflow preventers in the same way as the pipes. Do not cover or block the drain or air vents.
Prepare the vacuum breaker by leaving both the intake and outtake valves in a half-open position to prevent cracking from water freezing inside. The half-open position requires turning it 45 degrees.
Close the test ports halfway on the sides of the breaker to prevent cracking from water freezing inside.