Pressure Reducing Valves

The Pressure Reducing Valve is designed to regulate the high water pressure supplied by the city to a level that is safe for homes. It is installed on the main water line. This is most commonly in the front flower bed, but it could also be behind an access panel in an inside wall.

When the PRV goes bad, it can cause pressure and water flow issues, weird noises, or just start to leak. This is a common issue in our service area. PRVs typically last between 8 and 15 years before one of these symptoms start to appear. We have flat-rate pricing built for this repair and have all of the tools/parts needed on our trucks to take care of this efficiently. Call us now for more information and to get on the schedule, or keep reading for a more in-depth description of PRVs, how they fail, and how we replace them.

What is a PRV?

Water pressure to the home is like blood pressure to the human body. It needs to be within a certain range for everything to function properly and avoid sometimes serious consequences. The water pressure to the home should be between 40 and 80 pounds per square inch (PSI) according to plumbing code. All of the plumbing fixtures, supply lines, and water-using appliances are built to perform within this range. When the water pressure is higher than this, it usually doesn’t cause immediate issues, but it takes a toll over time by wearing out the plumbing faster and increasing the likelihood of leaks/floods.

Many cities in the North DFW area have high pressure. They often raise the water pressure over time to accommodate for municipal growth. If your house was built after the water pressure in the city was raised, then a Pressure Reducing Valve (PRV) was probably required upon construction. If the house was built before the PRV was required, you’ll need to check your pressure to see if one should be installed now.

This valve takes the high pressure supplied by the city and reduces it down to a level that is acceptable for homes. It is installed on the main water line where it comes into the home. This could be in the front flower bed (most homes built before 2010). It could also be behind an access panel in a wall inside the house or garage.

When they are first installed, these valves do exactly what they are supposed to, and your home’s plumbing is protected. The problem is, these valves will eventually go bad. When they do, there are several common water flow and water pressure symptoms that you might experience.

Symptoms of a Failing PRV

Low Pressure

Sometimes, when the PRV fails, it decreases the pressure and water flow across the entire system. This can gradually get worse over time and be difficult to notice. If you observe poor water pressure at different faucets throughout the home, this could be the reason. If you have good pressure when running one faucet but it drops significantly when another faucet is turned on, this is often a symptom of a failing PRV.


Pressure reducing valves can also start to cause weird noises whenever different faucets are turned on. This sometimes sounds like a humming, squealing, or knocking sound that happens regularly when you turn on different faucets throughout the house.

High Pressure

The PRV can also fail by allowing high water pressure into homes. Although this won’t affect your experience as much as low water pressure, this high pressure is wearing out the plumbing in your home. You may also notice water-hammer. This creates a banging noise in the walls whenever a faucet is quickly turned off. (This is especially common when the clothes washing machine is running.)


Finally, PRVs can fail by simply leaking. Because they are usually installed in the front flower bed, it will create a wet, soggy spot where this valve is located. Look inside the valve box (usually a rectangular or circular green lid) to see if there is standing water. This box may be buried and tough to locate.

Replacing a PRV

If any of these issues sound familiar, just give us a call. We can come run some tests to determine if you have a PRV and if it is starting to go bad. If it is, then we can replace it for you.

If the valve box is in the flower bed, we completely rebuild the water line to make the PRV and main shut off valve accessible and serviceable. We dig up the old box, cut out the old fittings, and bring the line up closer to the level of the soil. We install a new PRV and stainless steel ball valve. We install a new valve box and fill up the bottom with pea gravel to prevent the ingress of mud in the future. It’s a lot of work, but it is the way the box ought to have been installed in the first place.

Whenever a PRV is installed on the system, an expansion tank is also required on the water heater. Read more about the expansion tank on our expansion tank service page. If you already have a good expansion tank, no additional work will be required. If you don’t have any expansion tank, or if the one that is installed is compromised, then we’ll install a new one at the water heater during the work of replacing the PRV.

After the work is done, we put any disturbed landscaping back as neatly as possible and make it look like we were never there. At the end of the day, you’ll have a brand-new PRV that can be easily adjusted and serviced in the future as well as a new stainless steel ball valve that you can use to shut off the water to your home without needing any tools.

Legacy Plumbing is centrally located to provide fast service to North Dallas and surrounding suburbs. If you are looking for a North Dallas area plumber please call us today or complete our Online Request Form.

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