Backflow Preventer Leaking in Murrieta? 5 Causes and What to Do

Why is my backflow preventer leaking?

The five most common causes are a worn rubber seal or check valve, a cracked bonnet or body, a stuck poppet or float in a PVB, debris on a valve seat, and an RP relief valve that opens because of a pressure problem. Sun, heat and occasional winter freezes in the Murrieta hills wear the plastic and rubber parts faster.

1. Worn seals or check valves. Rubber parts harden with age and stop sealing.
2. Cracked body or bonnet. A hard freeze on a cold night can split an assembly that was not drained.
3. Stuck poppet on a PVB. Water spits from the top canopy when the sprinklers start.
4. Debris on the seat. Sand or scale from a line repair holds a valve open.
5. RP relief valve discharge. Steady flow from the bottom vent means the check valves are not holding.

A small drip at startup that stops in seconds can be normal on a PVB. A steady drip or spray is not.

How do I shut off a leaking backflow preventer?

Turn the two ball valves on the assembly so the handles sit across the pipe. The one closest to the supply side shuts off the water. If that does not stop the leak, the line feeding the assembly may be leaking too, so close the main water valve. Turn the irrigation controller to off so it does not try to run with no water.

If you are unsure where your shutoffs are, see our emergency water shut-off guide.

How can I prevent backflow preventer leaks?

• Have the assembly tested once a year, or as your water district requires.
• Drain it or wrap it with an insulated cover before rare freezing nights in the hills.
• Flush the line after any pipe repair so debris does not lodge in the valves.
• Check it for drips each time you change the sprinkler schedule.