Sprinkler Backflow Preventer Freeze in Colorado Springs

Updated November 7, 2026 · 5 min read

What a backflow preventer does

A sprinkler system connects to your drinking water. A backflow preventer is a one-way assembly that keeps water from the lawn lines (with fertilizer, soil and whatever else) from being pulled back into the household supply. Many Colorado Springs homes have a pressure vacuum breaker, a brass device on two pipes sticking up out of the ground, usually near the foundation by the water meter or the house shutoff. Others have a reduced pressure assembly or a double check valve.

They have to be installed high enough and out in the open so they can be tested. That also means they are exposed to cold air all winter.

Why they freeze and split

Water expands when it freezes. Inside a backflow preventer, water sits in the body, in the check valve area and in the test cocks. Even a small amount trapped in a closed chamber can crack the brass or pop the bonnet. A sprinkler line buried under the frost line may survive, but the part above ground will not.

Colorado Springs' weather makes this worse. A warm fall can tempt people to keep watering late, and then a cold front drops temperatures 30 or 40 degrees in a day. Above about 7,000 feet, in Monument, Black Forest and up in Woodland Park, freezes come sooner and hit harder.

When to winterize

Colorado Springs Utilities has noted that the weather makes it hard to pin down a single date, and that higher elevations should winterize earlier. The National Weather Service's climate data for Colorado Springs gives some useful anchors:

In practice, booking a blowout in early to mid October keeps you ahead of the hard freezes in most years. Irrigation companies get busy that month, so call in September. If a single cold night shows up before your appointment, close the irrigation shutoff and drain the backflow preventer, or at least cover it.

How a blowout works

A blowout pushes the water out of the lines with compressed air. A technician closes the irrigation supply, hooks a compressor to the system (often at a blowout port or a test cock on the backflow preventer), and runs each zone until only mist comes out of the heads. Then the backflow preventer is drained by opening its test cocks and valves partway, so no water stays trapped inside.

A few points to know:

• Too much air pressure can damage pipes and heads, which is why many homeowners hire this out.
• The ball valves on a pressure vacuum breaker are often left at a 45-degree angle for winter so water cannot sit trapped in the valve body.
• The irrigation shutoff inside the house needs to be fully closed. If it leaks, water keeps refilling the line all winter.
• Manual drain valves on some systems let you skip the compressor, but only if the system was built with them.

If the backflow preventer already cracked

Many people find the damage in spring, when they turn the water on and get a spray from the device. Others find it in winter when the irrigation shutoff inside was not fully closed or the crack is on the house side.

1. Close the irrigation shutoff inside the house. It is often in the basement or crawlspace, on a branch off the main line near where it enters.
2. If water is still running, close the main shutoff for the house.
3. Check where the water went. Look at the foundation, window wells and the basement wall closest to the device.
4. Call a plumber or irrigation tech to replace the backflow preventer. Ask whether it needs testing after installation.
5. Photograph everything before repairs if water got inside.

Water running along the foundation in winter can soak into expansive clay soil, fill a window well, or find a crack in the wall. That is how an outdoor sprinkler failure turns into a basement flooding call. Our posts on window well flooding and expansive soil and basement water explain those paths.

When the leak gets inside

If the crack is on a pipe that runs through the house, or the shutoff failed and water got into a finished basement, treat it like any other burst pipe cleanup. Shut the water off, get the wet carpet and drywall checked, and start drying. A local restoration crew will measure moisture in the walls and floor and set dehumidifiers and air movers.

What drives the cost is how much space got wet, whether the basement was finished, how long the water ran, what has to be removed, and whether the response happened at night or on a weekend. The company that inspects gives you the figure in writing before any work starts.

Insurance and the irrigation system

Many homeowners policies cover sudden water damage inside the house from a burst pipe, but outdoor equipment like a backflow preventer and the sprinkler system itself may have limited coverage or none. A freeze that happened because the system was never winterized can also be treated as a maintenance issue. Our post on whether homeowners insurance covers water damage in Colorado goes into that.

Spring startup

When you turn the system back on, usually after the last hard freeze, open the irrigation shutoff inside slowly. Then open the backflow preventer valves slowly, one at a time. Watch the assembly for leaks before running zones. If you are leaving the house empty for the winter, add the blowout to the checklist in our PCS move and vacant home post.

Sources and official resources

• Contractor license lookup (Pikes Peak Regional Building Department)
• Homeowners insurance help (Colorado Division of Insurance)
• IICRC: restoration industry standards body
• Colorado Springs weather warnings (National Weather Service, Pueblo)
• Flood insurance basics (FEMA FloodSmart)
• A Brief Guide to Mold, Moisture and Your Home (EPA)