RPZ stands for what in backflow prevention terminology?

• A. Reduced Pressure Zone Backflow Preventer
• B. Reduced Pressure Zone Valve
• C. Radial Pressure Zone Backflow
• D. Reduced Plumbing Zone

Answer: (A)

RPZ stands for Reduced Pressure Zone Backflow Preventer, a backflow prevention device that protects potable water by keeping a reduced pressure between the supply and the downstream line. It uses two check valves and a pressure-relief valve between them; if backflow conditions begin, the relief valve opens and vents to the downstream side, ensuring water cannot flow backward into the system. This arrangement guards against both backpressure and back-siphonage, making it suitable for high-hazard cross-connections. Because of its complexity and risk, RPZs are typically required to be tested annually by a certified tester and to be inspected and maintained. The other terms listed—Reduced Pressure Zone Valve, Radial Pressure Zone, and Reduced Plumbing Zone—are not correct terms for this device; only Reduced Pressure Zone Backflow Preventer accurately describes it.