Pressure-reducing valve

City mains can run at pressures well above what household fixtures and appliances are built for. A pressure-reducing valve, or PRV, knocks that down to a safe range, usually 50 to 60 PSI. Chronic high pressure shows up as banging pipes, dripping relief valves, and appliances that fail young, so it is worth checking if you have those symptoms.

Why high pressure quietly shortens the life of everything wet

Household fixtures, appliance valves, and flexible connectors are engineered for pressure of around 80 PSI or below, and plumbing code draws the line there for a reason. A home running at 90 or 100 PSI does not fail dramatically — it fails a little everywhere: faucet cartridges wear out, toilet fill valves hiss and run, washing machine hoses bulge, and the water heater's relief valve weeps. Because each failure looks unrelated, the underlying pressure problem often goes undiagnosed for years while it keeps buying parts. One working PRV removes the common cause.

A $15 gauge answers the question in two minutes

Screw an inexpensive pressure gauge onto a hose bib or the washing machine spigot and read it — over 80 PSI means you need a PRV or the one you have has failed. Check it at night too: municipal pressure often rises when neighborhood demand drops, so a daytime reading can hide the overnight spikes that hammer your system. PRVs themselves wear out after a decade or two; symptoms of a failing one include pressure that creeps up over hours, whistling or chattering near the meter, or wild swings between fixtures. Any PRV install also needs an expansion tank, since it closes the system.