Pressure Regulator Valve Leak Detection & Repair

The pressure regulator valve, sometimes called a pressure reducing valve or PRV, is a mechanical device installed on the main water supply line where it enters the home. Its job is to reduce the variable and often high pressure from the City of Smyrna Water and Sewer Division's distribution system to a safe, consistent pressure for household plumbing, typically between 50 and 80 pounds per square inch. Without a functioning PRV, supply pressure from the distribution system can reach 100 psi or more, which stresses every pipe fitting, flexible supply line, appliance connection, and fixture valve in the home.

In Smyrna, PRV failures accelerate the copper corrosion problem that already exists from soft water chemistry and pipe age. High supply pressure combined with the turbulence it creates at pipe fittings and bends produces erosion corrosion in copper that is more aggressive than the general pitting from water chemistry alone. Homes in Walker Park and Highland Park Smyrna with aging copper supply that also have a failing PRV tend to produce pinhole leaks at an accelerated rate compared to the same era copper at normal operating pressure. Replacing the PRV is therefore part of the long-term solution to the pinhole problem in these homes, not just a standalone fixture repair.

Signs of PRV Failure in a Smyrna Home

• High pressure at fixtures: Faucets and showerheads that spray forcefully, water hammer sounds when valves are closed quickly, and noisy pipe runs when fixtures are in use all suggest supply pressure above the normal range.
• Repeated flexible supply line failures: Flexible braided supply lines that fail repeatedly in the same home, particularly at toilet and faucet connections, are often failing from high pressure stress rather than from age alone.
• Repeated pressure relief valve discharge at the water heater: The pressure relief valve on the water heater opens to relieve excess pressure. If it discharges frequently, the cause is often high supply pressure rather than water heater temperature, particularly if the home also lacks an expansion tank.
• PRV body corrosion or weeping: The PRV body itself can develop external corrosion or weep water at its connections or at the adjustment screw housing. A weeping PRV is a plumbing leak in addition to a pressure regulation failure.
• Pressure reading above 80 psi: A pressure gauge installed at a hose bib or at the main is the definitive test. Supply pressure above 80 psi at the home's interior means the PRV is not functioning correctly or was never installed.

PRV Testing and Replacement

We test supply pressure at the main and at a downstream fixture to assess both the incoming pressure and the PRV's current output. A functioning PRV produces a consistent downstream pressure regardless of variation in the city supply pressure. A failing PRV either allows city pressure to pass through unregulated, fails to reduce pressure below 80 psi at its rated setting, or produces pressure fluctuations downstream that indicate the internal diaphragm or spring mechanism is failing.

PRV replacement in a Smyrna home requires shutting the main water supply, removing the existing valve, and installing a new PRV set to the appropriate pressure for the home's plumbing system. The new PRV is set to 60 to 70 psi for most Smyrna residential applications, which provides adequate flow while staying well below the threshold that stresses fittings and appliances. In homes where a whole-house repipe is also planned, PRV replacement is coordinated as part of that project to avoid disturbing the main supply line twice.

Expansion Tank Coordination

In Smyrna homes that have a check valve or backflow preventer on the main supply line, which is standard in most homes built or retrofitted after 1990, the plumbing system is a closed system. In a closed system, the thermal expansion of water heated in the water heater has nowhere to go except back into the supply pipes. An expansion tank absorbs this expansion, protecting the PRV, the water heater, and the supply fittings from cyclical pressure spikes. We evaluate expansion tank presence and condition during every PRV inspection and recommend installation or replacement when indicated. For more on the relationship between the PRV, expansion tank, and water heater pressure relief valve, see the water heater leak detection page.

Frequently Asked Questions