Years ago, in one of my more embarrassing moments, I learned the value of winterizing the sprinkler system. My spouse had shut the system off that fall, bleeding the lines dry. But on a warm January day while he was at work, I decided to water the trees the easy way by turning on the sprinklers.
Things were fine for a few days but then a hard cold snap settled in and froze the lines. Once things warmed up again, a broken pipe near the house began to leak. No, leak is an inadequate word here – water was gushing. This was the main line running to the valve box; a big, three-quarter inch pipe that can put out a lot of water.
I know the sounds of my house, and “fire hose” isn’t one of them, so I did the only thing that seemed logical: run around in a panicked circle a few times, then call my spouse at work.
After a moment of sheepish explanation on how water got into the lines, he told me to shut the water off to the sprinkler system until he got home to figure it out. You know that moment in the movies where the hero/heroine have to go into the dark tunnel filled with icky things? This is the same thing – it was a crawl space.
Some things I won’t do, so I ran to my neighbor for help. Matt is a brave man and a kind one, so he sighed and jumped into the darkness to go shut the line down. Years later, we three still remember every detail of that day.
With the record setting low, our gardens are saying goodbye for the season, and although we may get a few more weeks out of our plants, the time has come to start shutting the systems down. When to do this is a question haunting many, so it was with pleasure that I read the email Tip of the Week from the Associated Landscape Contractors of Colorado ( you can sign up to receive this too – just go to their website. This is a professional organization, not a company, so they won’t try to sell you something.):
“One simple precaution can save you $100 in sprinkler repairs and a world of grief,” their tip reads, “Every year that first early freeze catches homeowners off guard and the most expensive part of their sprinkler system freezes–often causing flooding and water damage. Then there’s the repair bill to fix the tiny part that froze.
“Protect the most expensive part in your sprinkler system: the backflow prevention device. This component is required on all systems because it keeps the water that’s in your sprinkler system from backing up into the domestic water inside the house. It’s also the most vulnerable part of your system if there’s a freeze. It’s usually located somewhere outside the home and next to the foundation.
“This precaution will help protect the backflow from early freezes and still allow you to run your sprinkler system until it’s winterized.
– Wrap the backflow device with a towel which provides insulation.
– Then wrap the device and towel with a plastic bag and secure with duct tape. The bag keeps moisture that can freeze out of the device.
“Be ready to take these additional precautions before winter sets in:
– Drain the backflow so there is no water left in the device. If you don’t know how to do this, call a pro.
– Winterize the system. You won’t be able to operate your sprinkler system after draining it, so you are ready for the final step of protection which is having the system winterized by blowing out the lines (pipes) with compressed air.
“For help with winterizing your irrigation system to prevent freeze damage, go to the ALCC website and click on Find a Pro, a service that helps you search for companies in your area.”
As a general guideline, get your sprinklers winterized before mid-November.
Gardening after five 
Great reminder to those with sprinkler systems. For other hose draggers like me, be sure to disconnect the hose at the faucet to prevent a similar situation. Thx too for the link to the ALC.
This problem is getting bigger everywhere. Here’s why: Some backflow devices can be buried and are less susceptible to freeze (like the Double Check Assembly or DCA).
Where I live (Waco, Texas), the city has ruled that our yards are a “high hazard” which require a backflow device that *cannot* be buried. It’s called a Reduced Pressure Zone (RP or RPZ) and is the most expensive kind of device. (For a picture of several kinds of backflow devices, here is a Canadian site that will help: http://www.plumbinghelp.ca/backflow.php) As water purveyors become more and more cautious (see also paranoid), we will likely see a spread of RPZ requirements–and incumbent winter-freeze problems.
It is worth the trouble to prepare now for winter if you have an exposed device. You can find “attractive” rock-looking covers that will make your exposed backflow device all cuddly and warm. In really frosty areas, you might even consider placing an incandescent light in the box–just to make sure. That’s not full proof if you get so cold for so long that your freeze goes really deep. Then, the ONLY effective method is blowing out everything and making double-sure your valve doesn’t seep.
What if you are like us and have to protect against the occasional hard freeze, but can’t go all winter without watering? There are just two scenarios: 1) your ground doesn’t freeze deep and the only thing you have to worry about is whatever is above ground. In that case the fiberglass “rock” enclosure will do just fine. Or, 2) your ground freezes deep enough to reach the supply lines. I would look for Sears to have a sale on their air compressors, because you’re going to have to blow out the lines after every necessary watering. Or, get your local irrigation pro’s cell phone number!
Doug Saylor is a Texas licensed landscape irrigator and can be reached at doug.s@rainstat.com
Doug, I can’t thank you enough for a great addition to this post, and also the link to the site for backflow devices! Thank you thank you!
Fantastic advice all the way around, particularly with the weather turning cold on us a bit earlier than in previous years.
I see you’ve been getting snow up your way…
Carol,
Yes, we are getting snow… and awfully cold temps. They’re forecasting 2 degrees tonight. This is pretty accurate according to the Farmers’ Almanac, but I’m not happy!