The water company says your device needs testing
For many property owners, backflow comes up as a letter. It arrives from the water utility, names a device at your address, and gives a deadline for a passing test. The letter rarely explains what the device does, who is allowed to test it, or what happens if the result is a fail.
Another version of the same problem is not knowing whether you have a device at all. A new irrigation system, a pool, a boiler, or a commercial use can all trigger a requirement. If any of that sounds familiar, the answers below are the ones people usually need first.
Backflow testing and prevention in Downey, CA keeps drinking water from being pulled backward by a pressure drop. It also confirms each year that the protection still works. A backflow assembly is a set of check valves that lets water flow only one way, from the public system into your property.
| Device | Where it is common | Testable? |
|---|---|---|
| Reduced pressure assembly | Commercial buildings, fire lines, higher-hazard uses | Yes, annually |
| Double check assembly | Lower-hazard commercial and fire service | Yes, annually |
| Pressure vacuum breaker | Residential and commercial irrigation | Yes, annually |
| Atmospheric vacuum breaker | Individual irrigation valves, some fixtures | Usually no |
| Hose bib vacuum breaker | Garden faucets | No, but cheap and worth having |
What to do when you get a test notice
- 1Read the deadline and the device description on the letter.
- 2Find the device on your property and photograph it, including any tag.
- 3Ask your utility which testers it accepts.
- 4Hire a tester and ask to see their certification.
- 5Keep the passing report and send it to the utility before the deadline.
Got a backflow notice?
Call and read us the letter. We will help you work out the next step.
Repair the assembly
- Failed test points to a worn check valve or seat
- A rebuild kit often fixes it
- The repair must be retested
- Lower cost than replacement
Replace the assembly
- Body is corroded or cracked
- Model is old and parts are scarce
- Installation does not meet current rules
- Repeated failures after rebuilds
How local utilities handle backflow
California regulations require public water suppliers to run cross-connection control programs. Each utility writes its own rules for who needs a device and when. The City of Downey's Public Works says it operates a backflow prevention program as part of its water services.
Golden State Water Company, which serves Norwalk, states in its 2026 water quality report that property owners are responsible for installing and maintaining required backflow assemblies. It says annual field testing by a certified backflow assembly tester keeps the protection working. It also notes that irrigation systems, pools and spas, boilers, and fire sprinklers commonly create cross-connections.
Assemblies are built to published standards, such as ASSE 1013 for reduced pressure types and ASSE 1015 for double check types. Installation follows the California Plumbing Code, built on the Uniform Plumbing Code (UPC). The takeaway is to check with your own utility. The state sets the framework, but the deadline, the list of accepted testers, and the paperwork come from the water supplier that serves your address.
A note on testers. Backflow testing must be done by someone certified for it, and utilities decide whose certification they accept. We do not ask you to take any company's word for it.
Ask any tester for their certification, confirm your utility accepts it, and keep the report. This site does not state that any company holds a certification, so verify before you hire.
What a backflow job looks like
Identify the device
Type, size, location, and any utility tag.
Test
A certified tester checks the check valves and relief valve.
Repair if needed
Failed parts are rebuilt or replaced, then retested.
Report
The passing result goes to the utility.
What affects backflow costs
Insurance note: backflow testing and repair are routine compliance costs, not insured losses. A contamination event is a different matter and is handled through the utility and your insurer.
Backflow questions from Downey and nearby cities
Look at the water line where it enters the property or near the irrigation system. A testable assembly has a brass or bronze body with small test cocks and shutoff valves. It often sits on a short run of pipe above ground or inside a green box. A small cap on a hose faucet is a simple vacuum breaker, which is not tested. If you are unsure, your utility's records show whether a device is on file for your address.
A testable assembly generally needs testing by a certified backflow assembly tester at installation and then at least once a year. Many water utilities keep a list of testers they accept. Ask any tester for their certification, and confirm with your utility that it recognizes it before you pay.
Utilities enforce cross-connection programs, and a notice usually carries a deadline. If the deadline passes without a passing test report, the utility can take further steps, which may include shutting off service to the property. Read the notice for the specific deadline and what it requires.
A failed test usually points to a worn check valve, a fouled seat, or a damaged relief valve. Many assemblies can be repaired with a rebuild kit, and the repair has to be retested. If the body is corroded or the model is obsolete, replacement may be the better value.
Irrigation systems are among the most common reasons a device is required, because fertilizer and pesticide can sit in lines connected to drinking water. The type of assembly, and whether it must be testable, depends on your utility's rules and the setup. Ask the utility, or ask us to review the installation.
The state sets the framework, but each water utility runs its own program, and rules can differ. Downey's Public Works says it runs a backflow prevention program. Golden State Water, which serves Norwalk, states that owners must install and maintain required assemblies and have them tested annually by a certified tester.
Backflow devices sit on the same line as your supply, so a problem with the line may involve our water service line repair service. Businesses often need both, and our commercial plumbing page explains what that covers. We also take calls in the Norwalk area.
The City of Downey Water Division runs a backflow prevention program. Businesses across Los Angeles County, from Downey Landing to the Promenade at Downey, are the kind of sites where assemblies and annual tests come up. Ask your own utility for its tester list before you hire anyone.
Deadline on a backflow notice?
Call the Downey line and we will help you plan the next step.
☎ Call (562) 488-9614