That Notice from the Water District Isn't Junk Mail
You got a letter from Cal Water or your local water district saying your backflow prevention device needs annual testing. It looks bureaucratic. Easy to ignore. But here's what happens if you don't respond: a second notice, then a final warning, then they disconnect your water service. No hearing, no appeal — just a shutoff tag on your meter until you comply.
The good news? Backflow testing takes 15-20 minutes, costs under $150, and we handle everything — the test, any needed repairs, and submitting the certification directly to your water district. You don't have to fill out forms, mail anything, or make follow-up calls. One visit, full compliance, done.
"Got the notice from Cal Water and ignored it twice. Then they threatened shutoff. Called GB Plumbing in a panic — they came out the next morning, tested the device, it passed, and they submitted the paperwork same day. Crisis averted in 20 minutes."
— San Mateo homeowner with irrigation system ★★★★★
Who Needs Backflow Testing?
If you have any of the following, your property likely requires an annual backflow test:
What We Test & How It Works
Backflow prevention devices come in several types — RPZ (Reduced Pressure Zone), DCVA (Double Check Valve Assembly), and PVB (Pressure Vacuum Breaker). Each requires slightly different testing procedures, but the process is straightforward:
Locate & Access
We find your backflow device (usually near the water meter or where irrigation connects to domestic supply), verify the make/model/serial number, and ensure test ports are accessible.
Calibrated Gauge Testing
Using a certified differential pressure gauge, we test each check valve and relief valve in the device against specific pressure thresholds mandated by the American Water Works Association (AWWA).
Pass or Repair
If the device passes all tests, we complete the certification. If it fails, we repair it on-site (usually a $75-$200 internal kit) and re-test immediately. Most repairs take 15-30 minutes.
Submit Certification
We complete the official test report and submit it directly to your water district — Cal Water, SFPUC, or your local provider. You receive a copy for your records. Compliance confirmed.
"We manage 12 commercial properties across San Mateo County. GB handles annual backflow testing on all of them — schedules everything, tests, repairs what needs it, and submits certifications. We haven't missed a compliance deadline in three years. One less thing to worry about."
— Commercial property management company, 12 properties ★★★★★
Backflow Services We Provide
Annual Certification Testing
The core service most people need. We test your device, verify it passes AWWA standards, and submit the certification to your water district before your deadline. Quick, affordable, and zero paperwork for you.
Failed Device Repair
Devices fail testing when internal seals wear out (typically every 5-8 years). We carry common repair kits and fix most failures on the first visit — test, repair, re-test, certify, all in one appointment.
New Device Installation
Building a new irrigation system? Adding fire sprinklers? Your project requires a backflow prevention device. We install RPZ, DCVA, and PVB assemblies sized correctly for your application and registered with your water district.
"Our RPZ valve failed the annual test — first time in 8 years. GB had the repair kit on the truck, replaced the internals in 20 minutes, re-tested, passed, and submitted the cert. All in one visit, under an hour total. That's how backflow testing should work."
— Hillsborough estate owner, RPZ repair ★★★★★
Serving All Bay Area Water Districts
We're familiar with compliance requirements for every local water provider:
- Cal Water — Burlingame, San Mateo, San Bruno, Millbrae
- SFPUC — San Francisco, Daly City
- Hillsborough Water — Hillsborough (Town-operated)
- Estero Municipal — Foster City, San Mateo (portions)
Each district has slightly different submission forms and deadlines — we handle all of it so you don't have to learn the process.
Stay Compliant — Without the Hassle
Backflow testing in 15-20 minutes, repair on-site if needed, certification submitted same day. One call to GB Plumbing keeps your water district happy and your service connected.
(650) 235-6443