Backflow testing & repair in Livermore, CA
Livermore (Alameda County) gets its water from 2 suppliers, and the one on your water bill sets your backflow rules:
- Livermore Municipal Water: you hire a certified tester. We test, file the results with Livermore Municipal Water, and repair failed devices.
- California Water Service – Livermore District: you hire a certified tester. We test, file the results with Cal Water Livermore, and repair failed devices.
- County
- Alameda County
- Water suppliers
- Livermore Municipal Water; California Water Service – Livermore District
- Annual test
- Livermore Municipal Water: owner hires a certified tester and Cal Water Livermore: owner hires a certified tester
- Our price
- $199 per device ($25 off for new customers), or from $180/year on a plan
- ZIP codes
- 94550, 94551
Livermore Municipal Water rules for Livermore customers
- Backflow devices on domestic, irrigation and fire service lines must be tested every year.
- The City mails a notice when devices are due, listing each assembly’s serial number, location and the test report due date.
- Backflow assemblies are owned by the customer.
Source: Livermore Municipal Water backflow program (official page), checked October 19, 2026.
Rules for new and replacement devices in Livermore
Livermore Municipal Water
- Main fire service lines use a double check detector assembly (DCDA); reduced pressure (RP) assemblies protect domestic lines.
Source: Livermore Municipal Water backflow program (official page).
Cal Water Livermore
- Only approved, testable backflow prevention assemblies may be installed at the water meter.
- Air gaps must also be inspected every year.
- The assembly installed must be the type Cal Water’s local cross-connection specialist specifies.
Source: Cal Water Livermore backflow program (official page).
Installing or replacing a device takes a licensed plumbing contractor, usually with a permit. We can refer you to one we trust, test the new device once it’s in, and make minor repairs to existing ones.
Backflow questions from Livermore property owners
Which water supplier serves Livermore?
Livermore is split between Livermore Municipal Water and California Water Service – Livermore District. Your water bill names your supplier, and its notice sets your backflow rules.
Who tests backflow devices for Livermore Municipal Water customers in Livermore?
Only Livermore Municipal Water-approved backflow testers may test in its service area; customers book a tester from the approved list.
Who tests backflow devices for Cal Water Livermore customers in Livermore?
Property owners are responsible for their backflow assemblies, which Cal Water requires to be inspected and tested every year by a certified backflow prevention assembly tester.
When is the backflow test due in Livermore for Livermore Municipal Water customers?
The City mails a notice when devices are due, listing each assembly’s serial number, location and the test report due date.