What Does a Pressure Reducing Valve (PRV) Do?
A pressure-reducing valve (PRV) plays a vital role in protecting your home's fresh water plumbing system from excessive water pressure. Most homes rely on municipal water supplies that regularly exceed safe household pressure levels. Without a PRV, that pressure could damage fixtures, appliances, and even your home's pipes.
Installed near where the main water line enters the home, the PRV automatically adjusts incoming pressure to a safe, consistent level. Inside the valve, a spring-loaded diaphragm reacts to changes in pressure.
When pressure increases, it tightens to restrict flow; when it drops, it opens slightly to allow more water through. The result is steady, balanced pressure throughout your home's fixtures.
However, when a PRV starts to wear down or becomes obstructed, that balance is lost. The device can overcompensate or underperform, leading to pressure fluctuations at your taps, showers, and appliances.
How Do I Know If My PRV Is Causing Water Pressure Issues?
Because your PRV controls the water pressure for your entire house, any malfunction will typically affect multiple fixtures, not just one. Five common signs that your PRV may be the source of pressure fluctuations include:
- Noticeable shifts in pressure when using multiple fixtures
- Water surging or pulsing from taps or showerheads
- Appliances like washing machines or dishwashers performing inconsistently
- Banging or rattling noises in pipes, known as water hammer
- A sudden drop or increase in overall household water pressure
If you're unsure whether your PRV is causing water pressure issues, you can test the pressure at an outdoor spigot using a pressure gauge, which can be purchased from most Home Depot stores. Most household plumbing systems should sit between 40 and 80 psi. If you notice wide swings above or below that range, your PRV may need to be inspected or replaced.
It's also worth noting that while a faulty PRV is a common culprit, it's not always the root cause. There are many causes of low water pressure in older homes — with corroded or narrowed pipes being one of the main culprits, which can make your PRV struggle to manage deeper plumbing issues.
For more information, see our article dedicated to how faulty PRVs can cause low water pressure throughout your home.
Can Mineral Buildup or Debris Affect PRV Performance?
Mineral buildup and debris are among the most common causes of PRV malfunction, especially in homes with hard water. Hard water contains naturally high levels of calcium and magnesium, which can leave behind limescale deposits inside your plumbing system and within the PRV itself.
Over time, these mineral deposits and bits of sediment from the water supply can accumulate inside the valve's internal components. When that happens, the PRV struggles to open and close properly, leading to inconsistent water pressure throughout your home.
Here are some of the typical ways mineral buildup and debris affect PRV performance:
- Valve sticking: Limescale can cause the PRV's moving parts to seize, preventing it from regulating pressure smoothly.
- Internal blockage: Sediment and mineral flakes can clog narrow valve passages, restricting water flow and causing sudden drops in pressure.
- Seal or diaphragm damage: Hard water minerals can degrade the rubber seals and diaphragms inside the valve, resulting in leaks or irregular performance.
If you're dealing with repeated PRV problems and live in an area known for hard water, the issue often extends beyond the valve itself. Mineral buildup inside the pipes can cause chronic pressure loss and flow restrictions.
In those cases, replacing or cleaning the PRV may offer only temporary relief. It may be time to consider a whole-home repipe to restore smooth, consistent pressure and protect your new PRV from future damage.
Will Repiping Help Prevent Future PRV Failures?
If mineral buildup or corrosion is causing frequent PRV issues, a whole-home repipe is often the most effective long-term solution.
Replacing old or scale-clogged pipes helps remove the root cause of those frustrating pressure fluctuations and protects new plumbing fixtures, including your PRV, from future problems.
In older homes, pipes made from outdated galvanized steel or old copper often develop rough internal surfaces that collect mineral deposits over time. This narrows the internal diameter of the pipe, reduces flow, and puts extra strain on the PRV. Replacing the valve alone won't fix pressure issues if the pipes themselves are restricted.
Modern piping materials like PEX (cross-linked polyethylene) can make a noticeable difference. PEX offers several advantages, including:
- Resistance to scale and corrosion: PEX doesn't react to minerals in the water the same way metal pipes do, so buildup is far less likely. This helps prevent the gradual narrowing of pipes that can force your PRV to overwork.
- Improved water flow: Smooth, seamless interior walls allow water to flow freely throughout your plumbing system, restoring even pressure to every fixture and reducing the risk of sudden surges or drops.
- Longevity: PEX is flexible, resistant to temperature changes, and less likely to crack or burst under pressure. Its durability helps ensure your plumbing and PRV perform reliably for decades to come.
When pressure fluctuations persist despite PRV adjustments, repiping can provide a permanent fix. Homeowners often notice stabilized water pressure and smoother operation of their PRV after a full repipe.
Repiping isn't just a repair; it's an investment in your plumbing system's long-term stability. By addressing the buildup and corrosion that strain your PRV, you extend the lifespan of your pipes and prevent future pressure problems before they start.
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If your water pressure keeps fluctuating even after replacing or adjusting your PRV, your plumbing system may need more than a quick fix. At Repipe Specialists, we've completed over 75,000 full-home repipes across the United States, restoring consistent water flow and long-term reliability to homes of all sizes. We often exceed our customers' expectations on:
- Speed: Our repipe crews typically complete a repipe in a day, returning on another day for wall patching.
- Convenience: Through our One-Stop Repipe™ Process, we handle everything from permits, to wall patching, to inspections.
- Cleanliness: Our crews are trained to protect your home while working (we cover all surfaces with protective sheeting), and to clean up fully at the end of each day.
- Peace of Mind: Repipe Specialists is a fully licensed plumber in every state we operate in, and we back all of our repipes with a lifetime warranty.
- Financing programs: To help take the sting out of unplanned repipe expenses, we offer several financing programs.
- Price: As a specialist that performs hundreds of repipes a week, we can deliver high quality repipes at a lower cost vs generalist plumbers. Our quotes typically range from $4,500 to $15,000 depending on the size and complexity of your project. We have an article that covers repipe cost factors in detail.
Say goodbye to unpredictable water pressure and failing valves. Schedule a free, no-obligation quote with one of our local Repipe Specialists today, and discover how a full-home repipe can provide consistent, high-pressure water for years to come.