Quick answer
A pressure reducing valve, or regulator, sits where the main line enters the house and lowers city pressure to a safe level, usually set around 50 to 60 psi. When it fails, pressure drops across the whole house, or rises too high, causing banging pipes, running toilets and a dripping water heater relief valve. Screw a pressure gauge onto an outdoor spigot: a reading above 80 psi, under about 40 psi, or one that creeps up overnight points to the valve. Call (888) 217-6781 to reach a plumbing company taking calls in your ZIP.
Follow the short menu, then your 5-digit ZIP. The line goes quiet for a few seconds while it connects; stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed November 4, 2026· Next review May 2027
Many homes on city water have a pressure reducing valve (PRV), also called a water pressure regulator, where the main line enters. City mains can run well above what household plumbing is designed for, and the valve lowers it to a steady level. When it wears out, it fails in one of two directions: pressure falls, or pressure climbs.
Six Signs It Is Failing
| Sign | What it means |
|---|---|
| Low pressure everywhere, came on suddenly or gradually | Valve stuck partly closed or clogged |
| Pressure that swings while you use water | Worn diaphragm or spring |
| Banging pipes when valves close | Pressure too high; see water pipes banging |
| Toilets running or refilling on their own | High pressure pushing past the fill valve |
| Water from the water heater relief valve | Pressure too high, or thermal expansion |
| Faucets that spit or hum | Pressure too high |
Test It With a Gauge
A hose-bib pressure gauge is inexpensive and settles the question.
- 1Screw the gauge onto an outdoor spigot or the laundry tap.
- 2With no water running in the house, open the spigot and read the static pressure.
- 3Leave the gauge on with the spigot open and check again after a few hours or overnight. A needle that has crept up means the valve is not holding.
Many plumbers set regulators around 50 to 60 psi, and plumbing codes commonly cap static pressure at 80 psi. A reading under about 40 psi explains weak showers; over 80 psi strains supply lines, washer hoses and water heaters.
Talk to a plumber about this
One call reaches a plumbing company taking calls in your ZIP.
Is It the Valve or Something Else?
- Neighbors have low pressure too: call the water utility.
- Only one fixture is weak: a clogged aerator or shower head; see low water pressure in the shower.
- Pressure is fine at the spigot but weak inside: old galvanized pipe; see galvanized pipes.
Adjusting and Replacing
Many valves have an adjusting screw on top. If turning it does not change the gauge reading, the valve is worn. Replacement is a common plumber job, and a new valve with a closed system may also call for a water heater expansion tank. See water heater expansion tank and low water pressure.
The Call
Call when the gauge reads above 80 psi, under 40 psi, or creeps up overnight, or when adjusting the valve changes nothing. (888) 217-6781 connects you to a plumbing company taking calls in your ZIP. Follow the short menu, enter your 5-digit ZIP and stay on while it connects; if it does not connect, call once more, because the companies taking calls change minute to minute.
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Frequently Asked Questions
What are the signs of a bad pressure reducing valve?
Low pressure throughout the house, sudden high pressure, banging pipes, toilets that run, faucets that spit, and water from the water heater relief valve. A gauge reading outside 40–80 psi, or one that rises overnight, confirms it.
What should my house water pressure be?
Many plumbers set regulators around 50 to 60 psi. Plumbing codes commonly cap static pressure at 80 psi.
How long does a pressure reducing valve last?
Often around 10 to 15 years, less with hard water or sediment.
Can I adjust a pressure reducing valve myself?
Many have an adjusting screw on top. If turning it does not change the gauge reading, or pressure keeps creeping up, the valve needs replacing.
Sources
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
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