A pressure reducing valve (PRV) reduces incoming water pressure to a safe level for your home\'s plumbing (typically 50–80 PSI). City water pressure can exceed 100 PSI, which stresses pipes, fixtures, and appliances. Signs your PRV is failing: water hammer (banging pipes), high water pressure at fixtures, or a PRV that\'s more than 10 years old. Well water homes don\'t typically need a PRV since the pressure tank controls pressure, but homes on city water should have one installed and tested periodically.