A sprinkler backflow device or sprinkler supply line that still holds water when the hard freezes arrive can crack, just like any other pipe. Most of the time the damage is outdoors and the fix is a plumbing or sprinkler repair. It becomes a water damage problem when the cracked part sits inside, or the sprinkler supply runs through a basement or garage wall, because then the leak ends up in the house when the system is turned back on.
What the Backflow Device Does
A backflow preventer stops water from a sprinkler system, which can pick up fertiliser, soil and lawn chemicals, from being drawn back into the drinking water supply. Homes whose sprinklers are fed from the house's culinary (drinking) water line need one, and it usually sits above ground near the house, with a couple of small valves and test ports on it. Homes whose sprinklers run on a separate secondary water system may have a different setup. If you're not sure which you have, the brass device near your foundation or the sprinkler valve box is the place to start looking.
Layton's Secondary Water Season
Much of Layton's sprinkler water comes from secondary water, which is untreated irrigation water delivered through its own pressurised system. In Layton, it comes from three providers: Weber Basin, Layton City (the former Kays Creek Irrigation system), and the Davis and Weber Counties Canal Company. Which one serves your address depends on where you live.
Secondary systems shut down for the winter. In 2026, Layton shut its secondary system early, on September 15, because of drought. That's earlier than many homeowners usually think about winterising. Lines that weren't blown out and drained after the water stopped are heading into the first freezes still partly full.
How Freeze Damage Happens
Water left in the sprinkler lines, the valves, or the backflow device freezes and expands. The parts most often damaged are:
- The backflow device itself. Its brass body or internal parts can crack or distort. Small test cocks and bonnets are common failure points.
- Above-ground piping leading to and from the device.
- The supply line where it leaves the house. If the sprinkler system is fed from inside, the pipe runs through the foundation or rim joist to the outside. The stretch through the wall is cold and exposed.
- Sprinkler valves in the valve box, if water stayed in them.
When It Becomes Damage Inside the House
Outdoor cracks spill water into the yard. The trouble starts when the leak is inside, or the water finds its way in:
- The shutoff and drain for a culinary-fed sprinkler line is often in the basement or garage. If that valve or the pipe next to it froze, the leak is indoors.
- A crack in the supply line where it passes through the rim joist can send water into the basement ceiling and down the inside of the foundation wall.
- A badly cracked device right against the foundation can push water along the outside of the wall, and in some cases it reaches the basement through a window well or a gap.
Like a split frost-free spigot, this kind of damage often shows up in spring, the first time the sprinkler supply is turned back on.
Signs to Watch For in Spring
- Water spraying or pooling at the backflow device when the system is first turned on
- A wet spot on the basement ceiling, rim joist or foundation wall where the sprinkler line goes out
- Damp drywall on the inside of the wall nearest the sprinkler connection
- Unusually low pressure at the sprinkler heads
- A rise in water usage on the culinary meter, if the sprinklers run on it
Getting Ready for Winter
- Turn off the sprinkler supply at its shutoff valve.
- Open the drain valve for the sprinkler line, if there is one, to empty the stretch between the house and the device.
- Have the lines blown out with compressed air. Many Utah homeowners hire this out each fall.
- After blowout, leave the backflow device's test cocks at a half-open position if that's what the installer or manufacturer recommends, so water can't sit trapped inside.
- Insulate exposed above-ground piping, and consider an insulated cover for the device.
Who Handles Which Part
Three different jobs can come out of one cracked sprinkler part. A plumber or a licensed sprinkler technician repairs or replaces the backflow device and the supply piping. Where the device is fed from the drinking water line, it may also need to be tested after the repair; your water provider can tell you whether that applies. A cleanup contractor deals with any water that reached the inside of the house: the basement ceiling, the rim joist insulation, the wall cavity and the flooring below. Ask each of them for their Utah license number and check it with the Division of Occupational and Professional Licensing (DOPL) before work starts.
If It Already Leaked Inside
Close the sprinkler supply valve and, if water keeps coming, the main. A plumber or sprinkler technician repairs the cracked part. The wet basement ceiling, rim joist insulation and wall are a separate job. The frozen pipe burst page explains how freeze leaks inside walls are found and dried, and appliance and supply line leaks covers other lines that fail outside the usual winter pattern.
Sprinkler water in a Layton basement or garage wall, in ZIP 84040 or 84041, is a job for a cleanup contractor once the line is shut off. (801) 788-4740 connects you with one; stay on while it routes.