On the city water line, which backflow prevention device is noted as requiring annual testing?

• A. Reduced Pressure Zone (RPZ) device
• B. Check Valve
• C. Vacuum Breaker
• D. Air Gap

Answer: (A)

Annual testing is required for backflow devices that have complex inner workings and a relief mechanism to ensure they actually stop backflow under pressure. The Reduced Pressure Zone device includes two check valves plus a relief valve, and its protection depends on the relief valve releasing if pressure differentials threaten backflow. Because small leaks or valve misadjustments can undermine protection, systems typically require a certified tester to perform an annual test to verify the device operates correctly and maintains the proper differential across its zones.

A simple check valve, while it can fail, is a more straightforward one-way component and isn’t universally mandated to be tested every year. A vacuum breaker provides backflow protection by venting to prevent back-siphonage but isn’t normally required to undergo annual testing in the same way RPZ devices are. An air gap is just a physical separation with no moving parts, so it doesn’t require testing.