Most water utilities and local cross-connection control programs require testable backflow prevention assemblies, like RPZ and double check devices, to be tested annually, but this is not a universal law — the exact frequency, required assembly types, and enforcement process are set by your local water purveyor. Before assuming your requirement, check the notice your water utility sends or contact their cross-connection control program directly.
Why Annual Testing Is So Common
Backflow prevention assemblies contain internal check valves, springs, and seals that can wear, stick, or degrade over time, and a device that passed inspection at installation isn't guaranteed to keep working correctly indefinitely. The EPA's guidance on cross-connection control explains that public water systems maintain cross-connection control programs specifically to protect drinking water from contamination that could occur if a backflow preventer failed silently. Routine testing catches failures before they become a public health risk, which is why annual testing has become the common default schedule adopted by many programs.
But It Varies by Jurisdiction
That said, "common" is not the same as "universal." Some water utilities test more frequently for high-hazard connections (such as certain industrial, medical, or irrigation-with-chemical-injection setups), and some allow longer intervals for certain low-hazard residential assemblies. States and municipalities also differ in how they define which assembly types are "testable" versus assemblies that only require periodic visual inspection. The only reliable source for your specific requirement is your local water utility's cross-connection control program — check your utility bill, your water provider's website, or call their backflow/cross-connection division directly.
Who Determines Testing Frequency
Cross-connection control programs are typically run at the state or local water-utility level, sometimes with state primacy agencies setting minimum standards that utilities then implement locally. This layered structure is part of why requirements differ so much between neighboring cities. If you own property across multiple service areas, don't assume the rules are the same — verify separately with each water utility.
What Happens If You Miss Your Test Window
Consequences for a missed annual test vary by utility, but common outcomes include a written notice, a compliance deadline, and in some cases a water service restriction or fee if the assembly isn't tested within the required window. Property managers and commercial building owners are often more closely tracked because of higher perceived cross-connection risk. If you've received a notice, don't wait — schedule promptly with a certified backflow tester and confirm with your utility how the completed test report needs to be submitted; see our guide on backflow test report filing for more on that process.
New Installations and Repairs
Beyond the routine annual cycle, most programs also require a test immediately after a backflow assembly is newly installed, relocated, or repaired — this confirms the device is functioning correctly before it goes back into service. If you've recently had a failed test and repair, plan on an additional re-test as part of that process, separate from your regular annual cycle.
FAQs
Is annual testing required everywhere in the US? No. While it's the most common interval, requirements are set locally by the water utility or state primacy agency, and specifics can differ. Always confirm with your own water provider.
Do all backflow assemblies need testing, or just some? Not necessarily all. Many programs distinguish between "testable" assemblies (like RPZ and double check valves, which have test cocks) and other backflow protection methods (like air gaps) that don't require the same testing process. Your utility's notice should specify which category applies to your device.
What if I don't have documentation of my last test? Contact your water utility's cross-connection control division — they typically maintain records of tested assemblies in their service area and can tell you your compliance status and next due date.
How to Choose and Verify a Backflow Testing Company
Whatever your local frequency requirement turns out to be, use a tester who holds current certification recognized in your area — typically an ASSE 5110 certification or equivalent — and who appears on your water utility's approved tester list. Confirm their test gauge is currently calibrated, since utilities can reject results from uncalibrated equipment.
This directory is an independent, source-backed listing of public records; it does not certify or endorse any provider. Confirm certification, approved-list status, and your exact testing frequency directly with your local water utility.