High Water Pressure and Pressure-Reducing Valves (PRVs)
Water pressure above roughly 80 psi feels great in the shower and slowly wrecks everything else — fixtures, supply lines, and water heaters all age faster under it.
What a PRV is
A pressure-reducing valve sits where the water service enters the home and steps municipal pressure down to a safe household level, typically in the 50–70 psi range. Many homes have one; many do not, or have one that failed years ago without anyone noticing.
The signs of high pressure
Banging or hammering pipes when valves close, faucets that spit or thump, running toilets that keep needing new fill valves, relief-valve discharge at the water heater, and repeated small leaks at supply lines. Any one of these can have other causes; several together usually point at pressure.
A simple gauge on a hose bibb reads the actual pressure in seconds — it is the cheapest diagnostic in plumbing.
Why it matters
Every washer, cartridge, fill valve, supply hose, and tank in the house is rated with normal household pressure in mind. Running them at 90 or 100 psi is like driving with the engine redlined — everything works, briefly. A failed PRV is one of the most common hidden causes of "this house eats fixtures."
Common questions
What should home water pressure be?
Most fixtures and appliances are designed for roughly 50–70 psi. Above about 80 psi, wear accelerates and many manufacturer warranties are affected.
How do I know if my PRV failed?
A hose-bibb gauge reading well above 80 psi, especially at night, is the tell. PRVs fail gradually, so the change often goes unnoticed for years.
Can high pressure damage a water heater?
Yes. Elevated pressure stresses the tank and can cause the temperature-and-pressure relief valve to discharge. Thermal expansion in a closed system compounds it, which is why expansion tanks are paired with PRVs.
Related Sonlight services
Related: PRV service, shutoff valves, and leak repair.