An occasional discharge from the relief valve of a RPZ indicates what?

An occasional discharge from the relief valve of a Reduced Pressure Zone (RPZ) assembly indicates that the device is working properly. The RPZ is designed to protect the potable water supply by preventing backflow due to back pressure or back siphonage. The relief valve functions as a safety mechanism that allows for the discharge of water when the pressure in the zone between the two check valves drops below the acceptable level or if the pressure upstream of the device becomes too high.

When the relief valve discharges occasionally, it signifies that the RPZ assembly is performing its intended role of maintaining a reduced pressure in the intermediate zone. This could occur during fluctuations in water supply pressure or when there is a temporary drop in pressure downstream. A steady or frequent discharge may warrant further investigation, but an occasional discharge is typically a normal function of the device and indicates that it is operating as designed to safeguard against potential backflow issues.