If you own or manage a commercial building, you’ve probably received a notice from your water provider asking for proof that your backflow preventer was tested. Here’s what that notice means and how to handle it.
What is backflow?
Normally, water flows one direction: from the public main into your building. Backflow is when water flows the other way — from your building back into the public supply. It can happen when pressure in the public system drops (for example, during a main break or heavy firefighting demand) or when pressure in your building rises above the supply pressure.
If that water carries contaminants, it can pollute drinking water for your neighbors. The connection points where that could happen are called cross-connections.
Why fire sprinkler lines matter
Water in fire sprinkler piping can sit stagnant for years. It may contain rust, sediment and, in some systems, additives such as antifreeze. That’s why fire sprinkler connections to the public water system are typically required to have a backflow prevention assembly.
Domestic water services for many commercial properties — restaurants, medical offices, car washes, irrigation systems and industrial users — may also require backflow protection depending on the hazard.
Common assembly types
- Double check valve assembly (DCVA) — two independent check valves; often used on lower-hazard connections such as many fire lines
- Double check detector assembly (DCDA) — a double check with a bypass meter to detect leaks or unauthorized use on fire lines
- Reduced pressure zone assembly (RPZ / RP) — a higher level of protection with a relief valve; used on higher-hazard connections
- Reduced pressure detector assembly (RPDA) — an RPZ with a detector bypass
The assembly type required is set by your water provider and applicable plumbing rules.
Who requires testing — and how often
Water providers operate cross-connection control programs and commonly require backflow assemblies to be tested at least annually, and also after installation or repair. In the Greater New Orleans area, requirements and submission processes vary by provider — the Sewerage & Water Board of New Orleans and parish water departments each set their own procedures. Follow the instructions on your notice, and ask your tester to confirm the correct submission format.
Testing must be performed by a properly certified backflow tester. In Louisiana, the Louisiana State Plumbing Board oversees credentials related to water supply protection; your water provider may also maintain its own list of accepted testers.
What happens during a test
- The tester confirms the assembly type, size, serial number and location.
- For fire lines, the impairment is coordinated — sprinkler protection is affected briefly while the assembly is tested.
- Using a calibrated test kit, the tester checks each check valve (and relief valve on an RPZ) against required pressure differentials.
- Results are recorded on the test form and submitted according to your provider’s process.
The test itself is usually quick, but plan for brief water interruption at the assembly.
If the assembly fails
Failures are common on older assemblies, often caused by debris, worn rubber parts or damaged springs. A failed assembly is usually repaired (rebuilt with a parts kit) and then retested. Some assemblies are replaced if they are obsolete or badly damaged. Your water provider may set a deadline for repair.
Key takeaways
- Backflow preventers protect the public water supply from contamination.
- Fire sprinkler connections typically require a backflow assembly.
- Water providers commonly require annual testing by a certified tester; procedures vary by provider.
- Coordinate fire-line backflow testing with sprinkler service.
Need a test before your deadline? See our backflow testing service or request a quote.
Sources & references
YearRound Editorial Team · Fire & Life Safety Education
Articles from the YearRound Fire & Life Safety team are written to help commercial property owners, facility managers and business operators understand their fire protection systems. Technical articles are reviewed for accuracy against current published standards before publication. Requirements vary by jurisdiction — always confirm with your local Authority Having Jurisdiction.