Reduced pressure zone (RPZ) backflow detectors monitor leaks and system usage, ensure media travels in one direction, and stop back-siphonage and back-pressure in high-hazard applications, such as medical facilities and manufacturing. Sudden drops in system pressure or downstream stoppages (back-siphonage) and outlet pressure exceeding inlet pressure (back-pressure) send flowing backward through the line. These preventers rely on pressure changes caused by back-siphonage and back-pressure to close the check valves, block the media's flow path, and prevent contaminants from entering the system. Along with the check valves, these preventers consist of pressure relief valves that automatically release backflow if pressure drops below the threshold for added protection, test ports for checking media, and shut-off valves on the inlet and outlet side of the unit to stop flow and conduct maintenance. RPZ backflow detectors can be paired with other alarms, sensors, and meters to send alerts, identify backflow, and measure flow rates.