What is a Water Pressure Regulator?

A water pressure regulator is a plumbing safety feature which is designed to prevent water pressure from climbing too high while also ensuring that the pressure remains high enough for consistent flow from faucets, taps, and shower heads. This device is often located near the water main on the outside of the house, and it is very useful for people to know where their water pressure regulators are, and how to adjust them if necessary.

Plumbing works because of the water pressure. When the pressure is high enough, water will be pushed through an open tap, even if the outlet for the water is well above ground level. However, pressure which is too high can result in leaks, eroded washers, banging pipes, and even explosions, in extreme circumstances. A water pressure regulator is a valve which controls the level of water pressure to ensure that it is effective and safe. In a multistory building, each floor may have a water pressure regulator in place, since higher levels of pressure are needed on high floors to successfully push the water up.

Classically, water pressure hovers somewhere between 40 pounds per square inch (2.8 kilograms per square centimeter) and 60 PSI (4.22 kilograms per square centimeter). Most water pressure regulators have an adjustable dial which can be used to increase the water pressure in the event that water is merely trickling out of taps, and to decrease the pressure if the water pressure is too strong. Some also have valves which open up in a pressure surge to allow water to harmlessly flow out, rather than blowing through the plumbing system.

Water heaters have a special type of water pressure regulator which is called a temperature pressure regulator valve (TPRV or TPR valve). The TPR valve is designed to open if the pressure or temperature inside the hot water heater grows to a dangerous level, allowing the pressure to vent harmlessly, albeit sometimes messily. If this valve becomes damaged or defective, there is a risk of an explosion caused by extremely high pressure inside the water heater.

Familiarizing oneself with safety features like water pressure regulators, main water cutoffs, and breaker boxes is a very good idea, so that they can be accessed quickly in an emergency. It is also a good idea to periodically test these safety features to ensure that they are working smoothly; it should be easy to turn the valve or knob with the assistance of a pair of pliers or vice grips, for example, and there should be no signs of corrosion, leakage, or stress on the surrounding joints.

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Discuss this Article

Post 13

How often do you replace a residential (single family home) water regulator? A plumber told us to replace the water regulator every six years. We have never replaced our regulator and it is 37 years old. Are we being misinformed?

Post 12

I live in a condo complex. Each building has two water heaters. Our complex is about 25 years old and in good condition. We have always had consistent water pressure and never had issues with water temperature or ever having hot water available at any time.

About a year ago, the HOA decided to replace the two water heaters with one for each building. Since then, I, along with several other neighbors, have experienced unexpected hot water surges. I am constantly being burned in the shower! My neighbors have had similar experiences. The neighbors complain of banging pipes in the walls. Recently, the pipes in my upstairs end unit attic (where all the buildings plumbing and ventilation are housed) have

been banging as well. I am hearing other neighbors in other buildings complain of similar issues.

The HOA does not help and I think is aware of everyone having issues, but is keeping us in the dark. Could it be possible that the HOA made a mistake in replacing two large water heaters with one extra large one? Could they have needed to make plumbing modifications to have one water heater instead of two do the same job?

Post 11

I have a unit on the 18th floor and the developer did not put the PRV on the heaters on floors 17 to 23. Please let me know if I need to add one to my heater or whether it is fine without one.

Post 9

I have just redone my taps in my bathroom to mixers. The problem is that the hot has very little pressure, but only on the mixes. The normal hot taps were OK. I got a plumber to rectify the problem, only to find that the cold had been reduced to the same pressure as the hot. The plumber put the pressure valve from near the geyser to outside low down. Can anyone help?

Post 8

There is a noise similar to running your fingernails across a wooden surface coming from my water regulator, and is followed by what sounds to be a spring moving up and down. It went away when I adjusted the water pressure higher. It returned a couple of months later. Is this fixable or should I just replace the regulator?

Post 7

It is best your not mess around with the pressure on your regulator. Have a specialist (plumber should do it) to make sure you have the correct pressure. 140 lbs. seems awfully high.

PRVs are adjustable, but they are only adjustable from 25-75psi. If the pressure is higher than that, it's either because of PRV failure or thermal expansion. Once a PRV fails, it is no longer adjustable. It's not just a matter of adjusting down the PRV. If the problem is coming from thermal expansion, the homeowners will need to have a thermal expansion tank installed on their water heaters to correct the high water pressure issues. Adjusting the PRV in this instance will also not do anything since it's not the source of the excessive pressure building in the system.

Post 6

There is a bang noise that seems to come from kitchen area, at nights. I have a water meter on pavement outside my drive.

The bang occurs at 11.40 p.m., 12.40, 1.40, and 2.40.

I have had plumbers and engineers to look at the system, boiler and pipework and they have no idea what causes it, especially as the boiler and appliances are off at night. This has happened both winter and summer.

Is it from a pressure control monitor? Should I contact Thames Water? V.N.

Post 5

The problem was with the water company. The water pressure was oscillating at the same time in the AM that I was hearing the sound and the pressure regulator in my house was ineffective. The water company fixed their problem and i replaced my pressure regulator. No more problem.

Post 4

duhamel: To me it sounds like a sprinkler system possibly causing this, especially since it occurs on a regular basis. Look around your property and close by properties and see if there is a sprinkler system running.

i have learned this from experience. My neighbor's system causes this in my house because our water meters are in the same common walkway between the houses but i only hear it in my downstairs bathroom early in the morning, roughly the same time as you experience your noise!

Post 2

how do you adjust a pressure regulator if I want to adjust it down. The meter reads 140 lbs of pressure so I need to adjust it down, right?

Post 1

Every morning about 6:15 AM a noise appears in my water line near the water pressure valve. It lasts for about 5 seconds and repeats every 16 seconds. It is like a short rumble. After daylight savings times started it moved to 7:15 for two weeks and now is back at 6:15. If I run water in my house the sound stops and is replaced by a hissing at the same regular intervals and it comes back when the water is stopped. After about an hour it just stops. The noise never happens at a different time in the day. My neighbor has a similar noise. Would something related to the water company pressure cause such a regular sound?

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