EBMUD Backflow Testing: A Homeowner's Guide for Oakland and the East Bay
East Bay Municipal Utility District, which almost everyone calls EBMUD, supplies water to a big stretch of the East Bay: Oakland, San Leandro, Castro Valley, Walnut Creek, Danville, Alamo and part of San Ramon, among others. If your property has a backflow preventer and EBMUD is your water supplier, you’ll get a notice when the annual test is due. What follows is what EBMUD asks for and how to get it done without a second letter.
What the device is protecting
A backflow preventer is a valve assembly, usually near the water meter, that keeps water from running backward out of your property and into EBMUD’s mains. Reverse flow can happen when pressure in a main drops, for example during a break or when firefighters draw heavily from hydrants. Without protection, whatever is connected to your plumbing (an irrigation system, a fire sprinkler line, a pool fill, a boiler) can be pulled into the water your neighbors drink.
Inside the assembly are check valves held shut by springs and sealed with rubber. Those parts wear, and debris from the main can stop them sealing. You can’t see either problem from outside, which is the whole reason for a yearly test with a gauge.
Who’s responsible
EBMUD is clear that the device belongs to you. On its backflow prevention page, EBMUD says the customer must install, test and maintain the required device and pays all of its costs. EBMUD runs the program, but it doesn’t test your device for you.
Who can test it
This part is easy to miss. EBMUD doesn’t accept a test from just any certified tester. The test has to be done by a tester on EBMUD’s approved backflow testers list, and getting on that list takes two things: certification as a general backflow tester from AWWA, ABPA, NCBPA or ASSE, and passing a written and hands-on exam given by EBMUD’s own backflow staff.
A tester who works in the East Bay regularly will know about the list, and it’s perfectly fair to ask about it when you book.
The deadline and how results are filed
EBMUD gives you 30 days from its notification. Unlike some suppliers that use online portals, EBMUD takes the completed test form by mail, sent to its Backflow Prevention Section in Oakland. Testers usually handle the form and the mailing, but confirm that when you book. Your job is to schedule the test early enough that the form arrives within the 30 days.
If you’re cutting it close, don’t wait for the last week. A device that fails needs a repair and a retest, and that all has to fit inside the same window.
What happens on the day
Most homeowners don’t need to be there. The tester needs access to the device, so unlock any cage or gate, then shuts off water at the assembly for a short time, connects a calibrated gauge and checks that each valve holds. On a reduced pressure assembly (an RP), the relief valve gets tested too. One accessible device doesn’t take long.
If everything passes, the paperwork goes to EBMUD and you’re set until next year’s notice.
If it fails
The most common reason a device fails is wear on the rubber parts inside the check valves or the relief valve. The repair is a manufacturer’s kit for that specific model, followed by a retest so a passing result can be filed with EBMUD.
If the body is cracked, the device froze, or parts are no longer available, it has to be replaced. That’s plumbing work that generally needs a permit and a licensed plumbing contractor.
A note for private well owners
If your property has a private well as well as EBMUD service, there’s an extra rule. Since July 1, 2025, EBMUD requires customers with private wells to test annually and submit the results under Section 26 of its regulations. If that’s you, mention the well when you book.
At BackflowCare, a standard test is $199 per device, with $25 off for new customers. You can book online, or see our EBMUD page for the district’s full requirements.
Common questions
Do I have to use a tester on EBMUD's approved list?
Yes. A backflow test from a tester who isn't on EBMUD's approved backflow testers list won't satisfy the notice.
How long do I have to test my backflow device with EBMUD?
EBMUD gives you 30 days from its notification to have the device tested and the completed test form returned.
Can I test my own backflow preventer in the EBMUD area?
Only if you're a certified general backflow tester who has passed EBMUD's written and hands-on exam and is on its approved list.
Do EBMUD customers with private wells need to test?
Yes. Since July 1, 2025, EBMUD requires customers with private wells to test annually and submit the results under Section 26 of its regulations.
Who do I call with questions about my EBMUD backflow notice?
EBMUD's backflow section at 510-287-0874.