Backflow assemblies are built to be serviced. The check modules, seats, springs and relief valve parts come out through bonnets on top, and manufacturers sell repair kits for many models. A well-made bronze body can outlast several sets of rubber parts.

That said, some devices on older Fullerton properties have been in place for decades. A model that has been discontinued, a body cracked by an impact or a device that no longer matches what the water supplier requires can turn a simple repair into a replacement.

Repair versus replacement

Rebuild or repair

  • Replaces discs, seats, springs or diaphragms inside the existing body.
  • Often done on the same visit as the test if parts are on hand.
  • Keeps the existing piping and location.
  • Needs a passing retest afterward.

Replace the assembly

  • A new approved assembly of the required type and size.
  • May involve repiping, new unions or moving the device.
  • May need a permit or the supplier's approval: check with the city.
  • Needs an initial test and a report for the new serial number.

Quick decision guide

  • IfOnly rubber parts or springs failed and a kit is availableThenRepair is usually the sensible choice.
  • IfThe body, bonnet or test cock threads are cracked or strippedThenReplacement is usually needed.
  • IfNo parts are made for the model any moreThenPlan on replacement.
  • IfThe supplier now requires a different device typeThenReplace with the required type, after confirming with the city.
  • IfIt fails every year for the same reasonThenAsk whether pressure, debris or installation is the root cause before replacing.

What moves the price either way

  • Device type: RP repairs involve more parts than a double check or PVB.
  • Size: larger commercial and fire line assemblies cost more to rebuild or replace.
  • Parts availability for that brand and model.
  • Access: a device in a deep box or behind a wall takes longer.
  • Shutdown needs at a business, including after-hours work.
  • Permit or inspection requirements for a replacement.
  • Whether the retest and report filing are included.

Questions to ask before you decide

  1. What failed, and what is the condition of the body and shutoffs?
  2. Is a repair kit available, and how quickly?
  3. If replacing, which approved models fit the required type and size?
  4. Will replacing the device require a permit or inspection here?
  5. Does the price include the test and filing for the new device?

Common questions

How long does a rebuilt assembly last?

It depends on water quality, sun, pressure events and debris. Annual testing is what tells you when it needs attention again.

Can I upgrade to a different brand?

Usually, if the new model is approved and the same required type and size. Ask the water supplier if you are unsure.

Who can replace a backflow assembly?

Replacement is plumbing work. Use a contractor with a CSLB license you have checked at cslb.ca.gov, and a certified tester for the test.

General information for Fullerton, not a quote or professional advice. In an emergency, call 911.