RPZ Assemblies offer the highest level of protection against backpressure, and are suitable for systems with health hazard risks. Double Check Valves provide moderate protection and are used for low- to medium-risk systems. Finally, Atmospheric or Pressure Vacuum Breakers protect against backsiphonage only and are used in simpler systems without high risks.

RPZ backflow preventers typically need to be tested once per year. Most states and local water authorities require annual testing by a certified backflow tester to ensure the device is working properly. RPZ assemblies may also need testing after installation, repairs, or relocation.

Water may discharge from an RPZ backflow preventer when the device is relieving excess pressure or preventing backflow contamination. RPZ assemblies include a relief valve that automatically opens if the pressure between the two internal check valves drops or if backpressure occurs. However, continuous or heavy leaking may indicate worn internal seals or a failing check valve.

An RPZ should be installed upstream of the sprinkler system, between the system and the potable water supply. Try to choose a location that is accessible for maintenance and testing. Install the RPZ valve above ground, and in a weather-protected area to prevent freezing.