Water Pressure Regulators: What They Are and How They Work

How a Pressure-Reducing Valve Works

The Spruce / Michela Buttignol

Water pressure regulators are made to reduce the flow of water into the home in order to limit the strain put on the plumbing infrastructure. Too much water pressure can cause many plumbing problems, so it is very important to keep the water pressure under control.

Although it is not necessary for every plumbing installation, a water pressure regulator can be essential in situations where the municipal water supply enters the home at a very high pressure, or where water pressure is irregular.

What Is a Water Pressure Regulator?

A water pressure regulator is a specialized type of valve that reduces the incoming water pressure to a manageable level for the home plumbing infrastructure. Water pressure regulators are typically installed where the main water line enters the home, just after the main shutoff valve.

If the water pressure is too high, it can cause significant damage to the valves, faucets, appliances, pipes, and plumbing fittings. When the system is protected by a water pressure regulator, there is less stress on the inner valves of appliances, faucets and shutoff valves will be less likely to leak, and fluctuations in water pressure are evened out.

What Is Normal for Water Pressure?

Most home plumbing fixtures are designed to work best at a pressure of about 50 psi (pounds per square inch), but it is not uncommon for municipal water supplies to enter the home with pressures as high as 150 or 200 psi. If such high pressure is present on a regular basis, the strain can eventually cause joints to fail, faucets and other fixtures to leak, and appliances to break down.

Clothes washers, dishwashers, and some other household appliances have built-in pressure regulators, but a whole-house water pressure regulator still offers protection to those appliances, and it also serves to protect all the pipes and fixtures throughout the house.

How Does a Water Pressure Regulator Work?

A water pressure regulator is a dome-shaped brass fitting that is generally found just past the main shutoff valve, where the main water line enters the house. It usually has an adjustment screw on top. Inside, a water pressure regulator has a variable spring-loaded diaphragm that automatically widens and narrows depending on the amount of water pressure entering the valve.

When the water enters the regulator at high pressure, the inner mechanism constricts the diaphragm to narrow the flow of water. This can reduce the pressure into a range of 50 to 80 psi, greatly reducing the stress on pipes and fixtures installed past the valve. On the other hand, when the incoming water pressure drops, the diagram opens wider to allow more water to flow through the valve. An adjustment screw on the top of the regulator can be tightened to increase the tension on the inner spring (thereby reducing the pressure of the water as it exits the valve), or loosened to allow water to flow more freely through the valve (thereby increasing the outgoing water pressure).

Do I Need a Water Pressure Regulator?

To find out if you need a water pressure regulator, test the water pressure of the main water supply to your house. You can buy simple pressure gauges at a local hardware or home improvement store. Screw the pressure gauge onto any hose bib or washing machine faucet and turn on the cold water tap to measure the water pressure. If the pressure is between 40 and 60 psi usually, then you should be fine, but water pressure over 80 psi is probably causing excessive stress on pipes, fittings, and fixtures.

City water pressure can fluctuate considerably, often increasing at night when the overall load goes down, so make sure to test at various times of the day. During the test, ensure that water isn't being used anywhere else in the house, such as at garden spigots or appliances. You can also ask your local water company, who will likely be able to tell you if a pressure regulator is recommended in your neighborhood.


Watch Now: How to Test Your Home's Water Pressure

Do I Have a Water Pressure Regulator?

To determine if you have a water pressure regulator, first locate where the main water line enters the building and find the main shut-off valve for the home. Typically, if you have a water pressure regulator it will be installed directly after the main shut-off valve.

If you cannot locate your main shut-off valve where the main line enters the home, then you should do a thorough inspection of the basement, garage, or crawlspace to find this valve. Alternately, the shut-off valve location may be listed in a home inspection report.

Once you have tracked down the shut-off valve, check the pipes downstream of the valve for a water pressure regulator. If you cannot find one after a lengthy investigation then it's likely that your home does not have a water pressure regulator.

How Long Do Water Pressure Regulators Last?

On average, a water pressure regulator can last from four to 12 years in a healthy plumbing system. However, most manufacturers recommended replacing water pressure regulators about once every five years to limit any potential damage high water pressure could have on the plumbing infrastructure.

If you notice water hammering of any type, or experience variations or inconsistencies in water pressure, it may be a sign that the water pressure regulator is no longer working properly. Testing the water pressure at least once a year is a good idea. If the regulator's adjustment screw no longer has any effect on changing the water pressure, it's time to replace the valve.

Remember that too much water pressure will put extra strain on the home’s plumbing systems and can cause toilets to run, faucets to drip, water hammer to occur in the walls, and in extreme cases, it can even cause burst pipes that can flood your house. So it's important to replace a failing water pressure regulator as soon as possible.

Common Water Pressure Regulator Problems

Installing a water pressure regulator is an excellent way to reduce the strain on your plumbing system and extend the life of your faucets, valves, and water-using appliances. However, a bad water pressure regulator can allow high water pressure to pass through into the home, so it's a good idea to familiarize yourself with some of the most common water pressure regulator problems, including fluctuating water pressure, high water pressure, low water pressure, leaking pipes, and noisy pipes.

Water pressure within a city system will often fluctuate during peak periods of the day when water demand is at its highest, but if your water pressure starts fluctuating with no discernible regularity or pattern, it may be due to a faulty water pressure regulator. Similarly, if you suddenly experience significantly higher or lower water pressure throughout the home, you should inspect the water pressure regulator for issues.

Other signs of water pressure regulator problems include leaking pipes, which can occur when the system is subjected to high water pressure for an extended period of time. Knocking sounds from the pipes, known as water hammering, can also be an indicator that high water pressure is taking a toll on the plumbing system. If you experience any of these issues, it may be time to replace the water pressure regulator.

How to Replace a Water Pressure Regulator

Replacing an existing water pressure regulator is relatively easy if the plumbing system is in good condition and the original installation was completed correctly. Ideally, a water pressure regulator should be installed immediately after the main valve with a set of threaded couplings to secure the water pressure regulator.

  1. Start the process by turning off the water to the home at the main shut-off valve.
  2. Open the faucet that is nearest to the main shut-off valve to drain excess water from the system.
  3. Position a bucket and towel under the existing water pressure regulator.
  4. Use a set of channel lock pliers to loosen the threaded couplings and remove the old water pressure regulator.
  5. Put the new water pressure regulator in position and hand-tighten the threaded couplings. Finish tightening the couplings with the channel lock pliers.
  6. Turn the water on at the main shut-off valve and check for leaks.
  7. Make sure to turn off the faucet you opened after allowing any air in the system to escape.

How to Install a Water Pressure Regulator

A new water pressure regulator installation is more difficult because the threaded couplings are not currently installed. Unless you are fairly experienced at plumbing work, it may be best to call in a plumber, as the installation may require repositioning the main water shutoff valve to create the necessary space for the water pressure regulator.

  1. Take a pressure measurement with a pressure gauge from a hose bib or washing machine faucet to get a baseline water pressure reading.
  2. Locate the main water shut-off valve for the home and turn the water off.
  3. Open the faucet nearest to the main shut-off valve to drain the water from the system.
  4. Use a tape measure to measure the length of the water pressure regulator with the threaded couplings attached, then mark this measurement on the pipe just after the main shut-off valve.
  5. Place a bucket and towel under the pipe where you are working, then use a pipe cutter to cut the pipe according to your previous measurement. The couplings will slide onto the ends of the remaining pipe, so make sure that you don't remove too much pipe during this step.
  6. Use grit cloth and a wire brush to clean the pipe and fittings, then apply flux paste to the pipe and fitting to help with the soldering process.
  7. Slide the threaded couplings over the pipe and apply heat to the fitting with the blow torch.
  8. When the fitting is hot enough, apply solder to the connection, allowing it to flow into the narrow gap between the fitting and the pipe. Repeat this process with the second coupling, then wait for the metal to cool down before proceeding.
  9. Once the threaded couplings are cool to the touch, you can put the water pressure regulator in place and hand-tighten the couplings. Finish tightening the couplings with the channel lock pliers.
  10. Turn on the water at the main shut-off valve and check for any leaks.
  11. Close the faucet your opened after allowing any trapped air to escape from the system.
  12. After installation, test the water pressure, and adjust the regulator, if necessary. To adjust, loosen the locknut on the adjustment screw, then turn the screw up or down until the water pressure is at the desired level, as measured by a pressure gauge attached to a threaded hose bib somewhere in the home.

How Much Do Water Pressure Regulators Cost?

The cost of a water pressure regulator installation depends on whether you hire a professional plumber to complete the work or if you have the necessary skills, knowledge, and experience for a DIY installation. Typically, water pressure regulators cost about $50 to $100 on average, though you could end up paying up to $200 depending on the size of incoming water line.

If you choose to complete this job on your own, you will need to purchase the necessary parts and tools, including threaded couplings, a pipe cutter, grit cloth, flux paste, solder, and a blow torch. This can significantly affect the cost if you don't already have the tools in your workshop. However, if you decide to hire a plumber to install the water pressure regulator the average cost for installation ranges from $250 to $450.

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  1. Learn how much it costs to replace a water pressure regulator - compose: Seo. (n.d.). https://www.homeadvisor.com/cost/plumbing/replace-water-pressure-regulator/