Winterizing Sprinklers

By Courtney Brown, Conservation Garden Park

As a person who migrated to Utah from a warmer climate, I had a few things to learn about how landscaping is different here. One of those lessons was learned the hard way. In the fall, I turned off the sprinkler system but did not know I needed to empty the lines. I got an unwelcome surprise the following spring; when I turned the system back on, I was alarmed by a rapidly-growing pool of water coming from a ten-foot split in the mainline PVC pipe that froze over the winter! It seems pipes are no match for the power of frozen water.

This problem can be avoided if you “winterize” your sprinkler system in the fall by removing any water that is still left in the lines after the system is turned off (unless you have a self-draining system, which should drain water automatically). You can call a pro to do this for you or take the project on yourself. Either way, come spring, you’ll be glad you did.

Call A Professional – Many landscape services companies will winterize your system for you. They’ll arrive with a large industrial air compressor, connect it to your sprinkler system, and open each valve to blow the water out of the pipes. It doesn’t take long, and should be relatively inexpensive. While they are there, why not have them check the system for problems? They can fix leaks, straighten sprinkler heads, or move sprinklers for better coverage.

Do It Yourself – It may take a little longer and not get every drop of water out of the pipes, but you can effectively winterize your sprinkler system using your own air compressor. You can blow the air from either end of the sprinkler system, but be sure you shut off the water supply to prevent the air from entering the main water supply. Open the sprinkler valve farthest away from the air source, then connect the air hose to the sprinkler main line. After the water exits through the sprinklers, disconnect the air hose from the pipe. While the air compressor is refilling, close the sprinkler valve and open the next one. Repeat the process until you reach the sprinkler valve closest to the air source.

Larger air compressors are more effective, but even a 2-gallon size compressor will hold enough air to remove most of the water from a section of your sprinkler system. You don’t need extremely high air pressure for this job, but you do need enough sustained volume to at least blow out one zone at a time. When using a small air compressor, you will likely need to disconnect the air hose after each zone and allow it to refill before opening the next valve.

A word of warning: always make sure you have at least one sprinkler valve open when the air compressor is connected! High air pressure can damage sprinkler system components. You shouldn’t need more than 100 p.s.i. of air pressure to get the job done, but you need it to be sustained long enough to remove most of the water from the pipes.

To learn more about landscaping in Utah, visit the Conservation Garden Park in person (now in full fall color) or visit online at

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