How do I know if my pressure reducing valve is bad?

Water leak Under

Not sure how to diagnose and fix or replace a water pressure reducing valve? 

In this article, your local plumbing experts explain the symptoms of a bad pressure reducing valve that may need to be replaced.

What is a PRV?

The Pressure Reducing Valve (PRV) protects your home from water pressure that is higher than what the plumbing fixtures in your home were designed to handle. By code, water pressure inside your house should be between 40-80 pounds per square inch (psi). If the water pressure delivered by your water supplier is higher than that, a pressure reducing valve is installed on the main water line serving the home to bring this down to an appropriate level.

The PRV won’t last forever, though. They are made with rubber parts and springs that will eventually wear out or get gummed up with particles in the water. Usually, PRVs fail slowly over time. It may take a while for you to notice there is an issue, especially if your usage habits aren’t very demanding.

When PRVs start to wear out, they can cause many strange issues with the water pressure throughout your home. As we go through these different symptoms, it is important to know that they will usually occur all over the house at the same time when they are caused by a failed PRV. If you are having any of these issues on only a single fixture in your home, then the issue probably isn’t with the PRV.

Now, here are five symptoms that could indicate that your pressure reducing valve is going bad.

1. Low or Fluctuating Water Pressure

If your water pressure doesn’t seem to be as strong as it once was or you notice a significant loss of pressure when you use more than one fixture at the same time, your pressure reducing valve may be bad. If you don’t usually use different tubs and showers at the same time, you may first notice this issue when you have guests over and the demand is higher than normal.

2. No Water Pressure

Although PRV issues usually happen slowly, sometimes problems can crop up overnight. If you have no water pressure throughout the house on both the hot and cold, your PRV may be bad. Make sure you check both the hot and cold water. If there is good pressure on the cold and not the hot it may be an issue with the water heater or the fixture itself.

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3. Hammering or Vibrating Noises

Repetitive knocking or consistent humming noises that seem to come from the walls when you run different fixtures are often caused by a failed PRV.

These noises can also be caused by other things as well, such as a failed expansion tank, quick closing solenoid valves on new appliances, bad vacuum breakers, faulty valves with loose washers, worn-out toilets fill valves, improperly strapped pipes, etc.

Sometimes it can be a combination of these contributing factors. For more confirmation that the sound is caused by the PRV, go to where it is located and listen. It should be noticeably louder right next to the PRV.

4. A Leak in your Flower Bed

Legacy Plumbing’s service area is on the north side of the Dallas Metroplex. Most of the PRVs around here are located on the main water line right where it comes up under the perimeter of the home in the front flower bed.

On homes built after 2010, it is more common to find them in other places. Check in the garage for a wall panel with plumbing pipes inside. We have also located them in the walls under stairs, closets, and laundry rooms.

Sometimes the valve itself will burst and start leaking. If you have a muddy or flooded spot in the flower bed, this could be the reason.

old gate valve and PRV

5. High Water Pressure

If your faucets, toilets, or appliances need frequent repair, this could be a symptom of high water pressure. Most fixtures are rated for a maximum working pressure of 80 psi. If you have a pressure that is continually higher than this, parts will wear out and things will break more quickly.

It is sometimes possible to adjust the pressure at the PRV to lower it. However, if the PRV is more than a few years old, this is often risky. By attempting to adjust it, it may stop working altogether or even start leaking.


If you’re noticing any of these symptoms, please contact us to schedule a service.

Hopefully, this information helps you out. If you have any questions, feel free to give Legacy Plumbing a call. We are happy to help in any way we can.



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