Winterize Your Lawn Irrigation System to Avoid Spring Headaches

Angie Hicks
Written by Angie Hicks
Updated October 28, 2013
A properly working sprinkler system will nourish the lawn. (Photo courtesy of Aaron Curtis)

If you’ve invested thousands of dollars in a lawn irrigation system, you need to take action now to keep from having to spend hundreds or thousands more next year.

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If you’ve invested thousands of dollars in a lawn irrigation system, you need to take action now to keep from having to spend hundreds or thousands more next year.

Irrigation winterization typically costs between $65 and $85, but it can save you hundreds, even thousands of dollars, on repairing or replacing a damaged system.

“If you don’t get it winterized, once the ground freezes, the pipes will burst from the water that is in there,” says Scott Lindborg, owner of Lindborg Irrigation in Fishers, Ind. “If the main line is not shut off, once that pipe bursts, you’re going to have a constant flow of water coming out in the yard. That will cause a bunch of problems. Your water bill will be high because of all the water you’re wasting, and in the spring you’ll have to go back and basically rerun a lot of the lines. If you don’t get it winterized, you’re asking for trouble.”

A professional experienced with irrigation systems will use an air compressor to “blowout” any water remaining in the underground pipelines. Typically, those pipes are made from rigid PVC plastic, which can shatter from expanding and contracting during the freeze/thaw cycle. Some systems also incorporate polyethylene pipes, which are more flexible and can expand, but the fittings compounds are usually still PVC and can crack if the lines are not properly drained.

“Because of the winters we’ve been having, with it being so severely cold, the ground can freeze up to three-feet deep,” says Norm Ransford of American Irrigation in Indianapolis. “If a pipe freezes, it just shatters like glass. It’s almost always a replacement situation after that. We might have to replace 10 feet of pipe or we might have to replace 100 feet of pipe on a large system. It’s just a matter of digging it up and replacing the pipe. That’s when it gets pricey and it’s why it’s well worth the price of a winterization.”

The brass backflow preventer valve — which keeps irrigation water from entering drinking water lines and is the only part of the irrigation system aboveground — can also crack and split if water is still in the lines. Replacing that could cost upwards of $300, Ransford says.

“When it expands and cracks, water starts shooting out of the valve itself,” Ransford says.

A blowout winterization is not a terribly challenging task — most professionals can do it in 30 minutes or less — but that doesn’t mean it’s a job for the do-it-yourselfer. If you don’t own an air compressor, renting one typically costs around $100. Plus, using too much air pressure can damage the system and potentially hurt the user. By not using enough pressure, the homeowner runs the risk of failing to fully clear the lines of remaining water. Most companies recommend a winterization by the end of November. Having your system winterized can also help you identify potential problems with your system.

“A lot of times, homeowners will run their system early in the morning and never actually see it running, so they might not spot anything wrong with it and we won’t get a service call,” Lindborg says. “But once we get out there and get the air turned on, it’s pretty easy to spot the water bubbling up or the air shooting out where it shouldn’t. So (winterizing) can help as far as diagnosing any problems. We can fix them on the spot or wait until the spring when we turn the (system) back on.”

Editor’s note: This article was originally published in October 29, 2011.

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