Backflow Preventer Testing: What SoCal Homeowners Need to Know
It's an unglamorous part of your irrigation system, but the backflow preventer does a critical job: keeping sprinkler water — and any fertilizer or contaminants in it — from flowing backward into your drinking water supply. Here's what Southern California homeowners need to know.
What a backflow preventer does
Under certain conditions (like a water main break or a drop in pressure), water can reverse direction and siphon backward through your sprinklers into the public water system. A backflow prevention device is a one-way gate that stops that from happening, protecting your home's and the community's drinking water.
Why testing is required
Because the stakes are public health, most Southern California water districts require backflow devices on irrigation systems to be tested annually by a certified tester. The internal parts can wear or stick over time, so testing confirms the device still works. You may receive a notice from your water provider when testing is due.
Common backflow issues
- Leaks or dripping from the device, often from worn internal parts or freeze damage.
- Failed test requiring repair or rebuild.
- Freeze damage on above-ground devices during rare cold snaps — insulating helps.
Keep it working
Have the device tested annually as required, protect it from freezing, and repair leaks promptly. A failed or leaking backflow preventer can also reduce your system's water pressure. Our irrigation team can inspect and service your device.
Frequently asked questions
Do I really need to test my backflow preventer?
In most Southern California water districts, yes — annual certified testing is required to protect the drinking water supply.
Why is my backflow preventer leaking?
Usually worn internal parts or freeze damage. It often needs a rebuild or replacement, which a certified tester can perform.
Arbol Roble has cared for Inland Empire landscapes since 1997, serving Rancho Cucamonga, Ontario, Fontana, Eastvale, Corona and Riverside. Request a free quote or browse our residential and commercial services.
About the Author
The Arbol Roble team are licensed landscaping and irrigation professionals (CSLB License #1077455) serving Rancho Cucamonga, Ontario, Fontana, Eastvale, Corona, Riverside, and the greater Inland Empire.