What Is a Pressure Reducing Valve (PRV)?
A pressure reducing valve, or PRV, is a valve installed near where water enters a building that reduces incoming municipal pressure to a safe level for household plumbing. Residential systems are generally designed for 40 to 80 psi, and municipal supply can be considerably higher. High pressure accelerates wear on every joint, fixture, and appliance in the system.
What high pressure actually does
Pressure above roughly 80 psi is a slow, system-wide destructive force rather than an acute problem, which is why it goes unnoticed for years. It stresses every joint continuously, shortens water heater life, causes supply lines and fixture cartridges to fail early, produces water hammer, and wastes water at every fixture.
A household experiencing repeated unexplained leaks at different points, failing fixture cartridges, and short water heater life often has a pressure problem rather than bad luck. Testing it costs almost nothing.
Testing and replacement
A threaded pressure gauge costs very little at a hardware store and screws onto any hose bibb or laundry connection. Anything above 80 psi warrants a PRV; anything above 100 psi is doing active damage.
PRVs themselves fail, typically after ten to fifteen years, and they fail in either direction: allowing full pressure through, or gradually strangling flow so the house seems to lose pressure. Replacement runs $250 to $600.
Frequently asked questions
How do I check my water pressure?
Buy a threaded pressure gauge, screw it onto an outdoor hose bibb or laundry connection, and open the tap fully. Test with no other water running. Anything over 80 psi should be reduced; over 100 psi is actively shortening the life of everything in the system.
Can a failing PRV cause low pressure?
Yes, and it is a commonly missed diagnosis. PRVs can fail by gradually restricting flow, producing a slow decline in household pressure that people attribute to municipal supply or to corroded pipe. Testing pressure before and after the valve identifies it quickly.
See also
Related services
- Whole-House RepipingReplacement of a home's supply piping where the existing system has reached end of life, using PEX or copper.
- Emergency Fixture Repair and InstallationRepair and replacement of faucets, shutoff valves, supply lines, garbage disposals, and other fixtures, including failed connections that leak.
- Emergency Leak DetectionNon-invasive location of hidden water leaks behind walls, under floors, and beneath slabs using acoustic, thermal, and pressure testing equipment.