After a cold winter: checking your backflow preventer before the first watering
Look for cracks, leaks and a wet base before the first watering. Backflow repair and installation starts at $800 on our price list.
Short answer: before the first watering of the year, look the backflow preventer over with the water still off, then open the supply slowly and watch it. Cracks, a bent handle, a constant drip or a wet base mean you should stop and have it looked at. Backflow repair and installation on our price list starts at $800. We repair and install backflow devices; we do not do testing or certification.
What this device does
Your irrigation line connects to the same supply that feeds your kitchen tap. The backflow preventer is the one-way gate that keeps lawn water, fertilizer and soil from being pulled back into the house supply if pressure drops. It usually sits above ground on a short run of pipe near the house or the meter, which makes it the most exposed piece of the system when a freeze arrives. It is also the first part to crack.
The visual check, with the water off
Do this before opening anything.
- Look at the body. Hairline cracks often run along the brass or plastic body. Use a flashlight and look at the underside.
- Look at the handles. Ball valve handles should turn smoothly. A handle that is bent, stuck or loose suggests something moved.
- Look at the base. A stained or eroded patch of soil under the device points to a slow leak from the previous season.
- Check the pipe. The pipe going into and out of the device should be straight and tight at the joints.
- Check the insulation or cover. If you covered it for winter, make sure nothing shifted or soaked through.
The check once the water is on
Open the supply slowly and stay beside the device for a minute.
- A spray from the top or the vent is a failed seal or a crack.
- A drip that slows and stops after a moment is often just air leaving the line.
- A drip that continues is worth a call.
- A hissing sound with every zone off means water is escaping somewhere.
Reading what you see
| What you notice | What it often means | What to do |
|---|---|---|
| Visible crack in the body | Freeze damage | Shut the supply and call |
| Continuous drip from the vent | Worn internal seal | Call for repair |
| Wet base, no active leak | Old seep or splash | Watch; call if it repeats |
| Handle will not turn | Corrosion or damage | Do not force it; call |
| Everything dry and quiet | Healthy for now | Carry on |
Why this is not a DIY repair for most owners
Internal parts of a backflow device are sized and arranged to a standard, and the device is a safety part. Swapping the wrong piece, or reassembling it wrong, can leave a path open for water to flow the wrong direction. Cosmetic fixes such as wrapping a crack in tape do not hold under line pressure.
A cracked body is generally a replacement, not a patch. That is where our $800 starting price applies, and the final figure depends on the device and how it is plumbed. Testing and certification are separate and are done by a certified tester, not by us.
Cheap fixes worth doing
- Clear mulch, leaves and weeds away from the device so you can see it.
- Make sure the box or cage, if you have one, is not trapping water.
- Note the shutoff valve location so you can close it fast.
If the device looks fine, the spring start-up visit on our irrigation page will go over it along with the zones, and that visit is $175 to $225 on the pricing page.
When to call us
Call when you see a crack, a steady leak, a handle that will not turn, or water pooling at the base. Shut off the supply to the system first if water is coming out. For a leak that appears in cold weather, shut it off and wait for the weather to ease before anyone digs. We stop and tell you before doing anything we could not see, so you know the number before the work. Request a quote if you want a look before the season starts.
FAQ
Why does the backflow preventer crack but the buried pipe survives? It sits above ground, where cold air reaches it directly. Buried lines are protected by the soil around them.
Is a small drip at the backflow preventer normal? A brief drip as air leaves the line can be. A drip that keeps going after the system has been on for a few minutes points to a worn seal or crack.
Can I tape or epoxy a cracked backflow preventer? We would not. It is a safety device under constant line pressure, and a patch can fail without warning.
What does backflow repair cost? It starts at $800 on our price list, covering repair and installation. Testing and certification are not part of that.
Prices from our price list. Updated October 2026.