What is the main purpose of a reduced pressure zone (RPZ) backflow preventer?

The main purpose of a reduced pressure zone (RPZ) backflow preventer is to prevent backpressure and backsiphonage in a plumbing system. This device is designed to protect the potable water supply by creating a physical barrier that prevents contaminated water from flowing backward into the clean water system.

RPZ backflow preventers achieve this by maintaining a reduced pressure zone between two check valves. The pressure in this zone must be less than the supply pressure, which ensures that any potential backflow from the system (whether due to backpressure or backsiphonage) is effectively blocked. This is particularly important in situations where there may be a risk of contaminants entering the water supply from various sources, such as irrigation systems or industrial processes.

Monitoring water quality, increasing water pressure, and functioning as a regular valve are not the main functions of an RPZ. While water quality monitoring is crucial for ensuring safety in water systems, it is not the role of the RPZ. Similarly, RPZs do not serve to increase water pressure or act as standard valves; their specific function is to maintain system integrity and prevent the reverse flow of potentially harmful substances into the potable water supply.