Water in the public main flows one way: toward your tap. A backflow device guards against the day that reverses, when a drop in street pressure could pull garden chemicals, pool water or boiler fluid back into the supply. Because springs wear out and seals foul, the device is tested rather than trusted. For the other specialist work our gas and specialty plumbing page covers, this one sits alongside it; below are the practicalities of the test.
Why did Torrance send me a backflow test notice?
A notice means a device on your property protects the public water system and is due its periodic check. Typical owners are those with an in-ground sprinkler system, a pool or spa, a fire sprinkler line, a boiler, or a commercial kitchen. Local testing firms say Torrance Municipal Water or California Water Service issues the notice, depending on who serves you.
Treat the notice as a deadline. The city's customer information page offers a Back Flow Test Report Form, which tells you the testing result is reported back to the water provider rather than kept by the homeowner. Keep the notice, the due date and the device location together, and read any instructions about who is permitted to test.
The State Water Board's cross-connection handbook, in effect since July 1, 2024, puts the minimum at one test a year and lets the board or a local health agency ask for more. If your notice quotes a different interval, follow the notice, because the supplier sets the rule for your address.
What happens when the tester arrives?
The tester closes the shutoffs around the device, bolts a gauge kit onto its test ports, and steps through each check valve and the relief port while reading pressures. A single device makes for a short visit. A passing result goes onto a form that is sent to the water provider.
The details vary by device type:
- Double check assembly. Two check valves in line; the tester confirms each holds against reverse pressure.
- Reduced pressure assembly. Adds a relief zone that vents water if a check fails, and the tester measures the pressure drop across it. This design suits higher-hazard connections.
- Air gap. A plain vertical gap with no moving parts, so it needs a visual check, not a gauge test.
Expect a brief water shutoff at the device, and on some assemblies a burst of noise or spray from the relief port. Landscaping around the device should be clear so the tester can reach it and the test cocks.
Can any plumber test my device?
No. The tester has to show the water supplier that they are qualified, usually through a recognized credential, and some suppliers keep a list of approved testers. The state handbook expects a valid tester qualification. A handyman or general plumber without one may see the report rejected when it is filed.
Ask three questions: Do you hold the tester qualification the water provider accepts? Will you file the report with the provider for me? What is your price per device, and does it include the filing?
In California the contractor license rule starts at a thousand dollars of work. A routine test falls well under it, but a replacement or a change to nearby pipe may not, so verify the license number with CSLB before you agree.
How much should one device cost to test?
Testing is priced per device, so a property with several devices pays for each one, and the written quote sets the price. Bigger devices, awkward access, retests and filing fees raise it. Repairs are billed separately once the test shows what is wrong. Ask for that quote in writing before the test is booked.
| Item | How it is usually priced |
|---|---|
| Test of one small residential device | per device, quoted in writing |
| Each additional device at the same property | often discounted; ask |
| Retest after repair | usually quoted separately |
| Replacement of a failed device | quoted after inspection |
None of these is a Torrance price list. Rely on the written quote. More on pricing sits in backflow device testing cost, while businesses with several devices should start at commercial backflow testing.
What if the device fails?
When a device fails, it cannot be relied on to stop reverse flow. Someone repairs or swaps it, and a retest has to pass before the provider gets a clean report. Common culprits are a worn rubber seat, a fouled check and a stuck relief valve, any of which a rebuild kit may cure. An old unit may be better replaced than rebuilt again.
Providers set a deadline for the corrected result, so ask yours what happens if it passes unmet. If a replacement is needed, find out whether a plumbing permit applies and who requests it from the City of Torrance Building and Safety Division.
Common questions
Must I stand by during the test?
Not the whole time, though an adult should unlock the gate, point to the device and agree the price. Water to the property is briefly interrupted, so skip showers, laundry and irrigation cycles during the appointment, and move any parked car or planter that blocks the path to the device.
Could I test it myself?
No. Water providers accept reports only from testers they recognize, and gauge kits need regular calibration, which is why homeowner readings do not count. What you can do is cut back plants around the device, keep its cover clear, and hand the notice to whoever comes.
Does a house with no sprinklers need one?
Not necessarily, because the device answers one specific hazard, whether that is irrigation, a pool, fire sprinklers or a boiler. If a notice reached you, a device exists at your address. Otherwise ask the water provider which devices it has on record for the property.
How often does this come around?
The state handbook sets a floor of once a year, and a repair or move of the device means another test. Your water provider's notice is the rule for your address, so follow its schedule and keep every report in a folder.
Where do I begin?
Dig out the notice, find the device, and jot down its make and model if they are printed on it. Pass what you have to us on the quote page and we line up a local plumber to test it or price a repair. The Del Amo Plumbing home page and plumber service in Torrance list our other work.
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