Winterize your sprinkler system
Water left in sprinkler pipes freezes and cracks them. Here is what a proper shutdown includes, and the part to leave to a pro.
Step by step
Schedule the shutdown before the first hard freeze.
Leave the controller powered and set it to OFF or rain mode.
Shut off the main water valve to the irrigation system.
If the system has drain valves, open them. Lines settle and form low spots over time, so most systems still need a blowout.
Have a professional blow out each zone with compressed air. The compressor connects downstream of the backflow preventer, and air should never pass through the backflow itself.
After draining, leave the backflow preventer's ball valves about half open (at a 45° angle) and its test cocks open. Fully open or fully closed valves can trap water and crack.
Wrap the backflow preventer and its exposed pipes in insulation down to the ground, cover it with plastic and tape it.
Safety first. A DIY blowout with a home compressor can injure you and damage the system. Manufacturers set strict pressure limits and require eye protection, and a zone valve must always be open while air runs. This step is best left to an irrigation professional.