A pressure reducing valve (PRV) regulates the pressure coming in from the water main, which can fluctuate from 50 to more than 150 PSI, depending on the area. The PRV helps protect dishwashers, clothes washers, and other appliances from the strain of high-pressure water. Building codes require PRVs, although older homes may lack them.
PRVs have moving parts; they eventually wear out and need to be replaced. If a PRV fails suddenly, it can rupture supply lines and cause flooding.
Signs that your PRV is failing could include “water hammer” (banging or thumping noises when your dishwasher or washing machine turns on or off) or a leaking Temperature and Pressure (T&P) valve on the side of your water heater.
If you suspect your PRV is failing, call a licensed plumber to diagnose and fix the problem.