A failed backflow test means one or more internal components, most often a check valve or a relief valve, didn't meet the required performance specification during testing. This doesn't necessarily mean the entire assembly needs replacement — many failures are repairable with a rebuild kit — but it does mean the device must be fixed and re-tested before your water utility will consider it compliant again.
Why Backflow Assemblies Fail
Internal components like check valves, springs, and seals wear over time, and debris in the water line can also prevent a valve from seating properly. A relief valve on an RPZ assembly may fail to open at the correct pressure if it has become fouled or if internal parts have degraded. None of this is unusual — it's part of why testing exists in the first place. The EPA's cross-connection control guidance frames periodic testing as a way to catch exactly this kind of gradual internal wear before it compromises the assembly's protective function.
What Happens Immediately After a Failure
Your tester should document the failure on the test report, noting which component(s) didn't meet spec. Depending on your water utility's process, this failed report may need to be submitted just like a passing one — see backflow test report filing — so the utility has a record that repair is in progress. Many utilities set a deadline (often a matter of days to a few weeks, though this varies locally) by which the assembly must be repaired and successfully re-tested.
Repair Options: Rebuild vs. Replace
Rebuild kits are often the more economical option when the assembly's body is otherwise sound. A rebuild kit replaces the internal wear components — seats, springs, discs, and seals — without swapping out the entire device. This is common for both double check and RPZ assemblies.
Full replacement becomes necessary when the assembly body itself is damaged, corroded, or when replacement parts for an older or discontinued model are no longer available. Replacement is generally more expensive than a rebuild but may be more cost-effective long-term if the device is old or has failed repeatedly.
Cost drivers to expect: the size of the assembly, whether it's a double check or RPZ (RPZ rebuild kits tend to have more components), accessibility, and local labor rates all affect repair pricing. Because these vary so much, get a written estimate rather than assuming a price based on general guidance — costs can range widely from a modest parts-and-labor rebuild to a more significant expense for full replacement of a larger commercial assembly.
The Re-Test Requirement
After repair, the assembly must be re-tested to confirm the fix actually resolved the issue — a repair alone doesn't restore compliance status until it's verified. Many backflow testing companies include the re-test in their repair quote since they're already on-site; others charge a separate trip fee. Ask about this upfront when getting a repair estimate.
Don't Ignore a Failed Report
Letting a failed assembly sit unaddressed carries real risk beyond compliance paperwork: a failed check valve or relief valve means the protection the device is supposed to provide may not be functioning, which is precisely the cross-connection risk these programs exist to prevent. Beyond the public health rationale, most water utilities will escalate an unresolved failure — potentially with fees or service restrictions — so prompt repair also protects you from added costs and hassle.
FAQs
Can I use a different company for the repair than the one that tested it? Generally yes, though whoever performs the re-test after repair still needs to be a certified tester recognized by your water utility.
Is a rebuild kit as reliable as a new assembly? A quality rebuild using OEM-compatible parts, properly installed, is generally considered a legitimate long-term fix. However, a device with a history of repeated failures may be a candidate for replacement instead — ask your tester for their honest assessment.
How quickly do I need to get this fixed? Timelines vary by water utility, so check your failure notice or contact your provider's cross-connection control division for your specific deadline.
How to Choose and Verify a Backflow Testing Company
For both the repair and the required re-test, confirm the technician holds current certification — typically ASSE 5110 or your state's equivalent — and is on your water utility's approved tester list. Ask whether their test gauge has a current calibration certificate, since a re-test performed with uncalibrated equipment may not be accepted.
This directory is an independent, source-backed listing of public records and does not certify or endorse any backflow testing company. Verify certification and approved-list status directly with your local water utility.