High Water Pressure (Missing or Failing Pressure Reducing Valve – PRV)
Water pressure in municipal systems can vary widely and sometimes enters homes at levels much higher than recommended for residential plumbing. A Pressure Reducing Valve (PRV) is a mechanical device installed on the main water line to lower incoming pressure to a safe, consistent level for the home’s plumbing system.
Why it matters:
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Excessive Wear and Tear: High water pressure (over 80 psi) puts stress on pipes, water heaters, faucets, toilets, and appliances. Over time, this can cause leaks, burst pipes, and premature failure of plumbing fixtures.
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Hidden Leaks: Pipes and fittings may develop slow leaks behind walls or under the home, leading to water damage and mold growth that isn’t immediately visible.
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Noisy Plumbing: High pressure often causes banging pipes (water hammer), noisy appliances, and toilets that run or hiss after flushing.
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Voided Warranties: Many plumbing fixture and appliance manufacturers void warranties if damage is caused by excessive water pressure.
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Increased Utility Bills: Leaks and running toilets caused by high pressure can waste significant amounts of water, raising utility costs.
What to check:
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Pressure Test: A plumber or home inspector can quickly test the home’s water pressure at an exterior hose bib or laundry connection. Safe pressure is typically between 40–80 psi; anything above 80 psi is a code violation in most areas.
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PRV Location: The PRV is usually found near the main water shutoff, often just inside where the main line enters the home or in a basement/crawlspace. It looks like a bell-shaped brass or bronze device.
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Signs of Failure: Look for signs of corrosion, leaks, or mineral buildup around the PRV. If the home has persistently high pressure, fluctuating pressure, or noisy pipes, the PRV may be missing or failing.
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Age and Maintenance: PRVs generally last 7–12 years. Older valves may stick, fail to regulate pressure, or leak. It is not recommended to try and clean or rebuild a PRV as these may fail and the cost of replacing is not significantly more.
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What to do if there’s a problem:
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If high pressure is detected and no PRV is present, one should be installed to bring the system into code compliance and protect the home’s plumbing.
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If the PRV is present but not functioning properly, it should be replaced by a licensed plumber.
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Bottom Line:
Maintaining proper water pressure with a working PRV is essential for protecting your home’s plumbing, ensuring code compliance, and preventing expensive repairs down the road.