Under Pressure: What It Means When You Have Too Much or Too Little Indoor Water Pressure

Most homeowners probably think water pressure is something that just comes with the home. When my family moved into a mid-century home in Provo, we quickly discovered the water pressure was really high and just assumed it was a harmless feature of the house. Besides, it was great for filling pots quickly and enjoying a high-pressured, exfoliating shower. However, what we didn’t realize was that this high pressure was actually really hard on our pipes and appliances. In this post, I’m going to be talking about water pressure, how it works, and what you can do if yours is either too high or too low.

There are technical ways of checking the water pressure in your home but one of the easiest signs that you have too much pressure in your plumbing system is that water seems to gush out of your faucets at, well, high pressure. You might also notice leaks from different fixtures in the home, like multiple dripping faucets. In our home, nearly all of the faucets leaked.

water pressure in your home - water pressure gauge

Another clue would be if you turn on the kitchen faucet, for example, and the faucet jumps or moves--or, if you turn on the faucet and the water comes out really hard and fast for half a second and then slows down. This could be a sign of high water pressure that isn’t being regulated. You could also hear a knocking or thunking sound coming from inside the plumbing when you turn on the faucet--another sign that the pressure is too high and is putting strain on the pipes and plumbing leading to your sink.

1. WHY IS HIGH WATER PRESSURE BAD?

As I mentioned, there might be reasons why people enjoy high water pressure. However, what you can’t see is that the perceived convenience of high water pressure is actually causing a lot of trouble around the house. For example, the pressure causes small pinholes to form in your pipes that start as small leaks but can lead to much larger ones. It also wears down the seals and o-rings in your plumbing system, faucets, and toilets. Additionally, the pressure puts undue stress on appliances like the washer, dishwasher, and water heater, shortening their lifespans. Regulating the water pressure in your home protects your pipes, your appliances, and your fixtures.

2. SO WHAT CAUSES HIGH WATER PRESSURE AND HOW DO YOU REGULATE IT?

The Pressure Regulating Valve (PRV) can be found right above your home’s main shutoff valve and is the part responsible for regulating water pressure in your system’s plumbing. Click here to watch a video helping you find your home’s water shutoff valve. As its name suggests, it regulates pressure as water comes into your home from the city line. It has a rubber bladder that activates when the pressure is high, ensuring that water within the closed system of your home is at a consistent psi.

Throughout the US, code states that water must be kept below 80lbs of pressure. Therefore, all the fixtures in your house are engineered to operate at that pressure. Because o-rings can fail and water can be abrasive at these pressures, anything over that point needs a regulator. However, many homes built before the 90s--and even during the 90s--were built without PRVs to keep the pressure in check. It hadn’t been put into code yet. So, if you live in an older home, there’s a possibility that your home doesn’t have a PRV, just as we discovered ours didn’t.

However, just because you have a PRV, this doesn’t mean it’s fully doing its job. PRV valves can last anywhere from 6 to 12 years, depending on how much sediment is in your water, as well as how much pressure you have coming into your house. Sometimes they can become stopped up by sediment and need to be cleaned out or replaced. The bladder inside can potentially calcify and fail as well. When the PRV valve fails, you will notice that either the valve failed in an open position, resulting in high pressure, or a semi-closed position, resulting in low volume and water pressure.

3. WHAT IF THE WATER PRESSURE IN YOUR HOME IS TOO LOW?

This problem is another one that’s easy to spot. If you put your faucets on full blast but the water comes out slowly, you’ve likely got a low pressure problem in your house. Fortunately, this problem is more of an annoyance than a hazard to your appliances. However, as far as your indoor plumbing goes, it could be evidence of problems lurking in your pipes or, as mentioned above, it could mean you have a failed PRV. Whether it’s a blockage or a leak in the pipe, if the water is coming out too slowly, you should probably get your plumbing inspected by a licensed plumber. They can identify where the slowdown might be occurring and help you figure out how to fix it.

Importantly, the PRV can reduce pressure but there’s no way for a PRV to increase pressure. The water pressure from your city’s lines is the highest your water pressure can go. However, technically if your pressure is lower, having a PRV isn’t a bad idea anyway. City pressure can change as there is new development or improvements to city lines, etc. But high pressure in the lines is trouble, making a PRV pretty much essential to any home.

4. HOW DO YOU TEST YOUR WATER PRESSURE?

You need a gauge to test whether you are getting either too much or not enough water pressure. Attach it to a faucet close to the water meter and make sure the system pressure isn’t exceeding 80psi. You can also measure it at the water heater. It’s important to check it at different times, as pressure can fluctuate throughout the day. You’ll also want to turn on multiple faucets in the house to see if the pressure changes as other faucets are opened. You’ll want to do this with another person so one can be monitoring the gauge while the other is turning on a faucet elsewhere. Once the pressure gauge regulates, turn the water off and check what .psi the pressure climbs back up to. Be sure to watch it for a while. A drop in pressure of 5-15 degrees when the faucet is opened is considered a normal flow. As long as it goes down at a normal rate, you’re fine. If you shut the water off and the needle jumps and bounces around, you either don’t have a PRV or it has failed.

If you find that you have consistently high pressure, you’ll want to either install a PRV or replace an existing PRV that may have worn out. Call a licensed plumber to help with installation; your plumber will also set the valve to operate effectively under that 80psi limit.

Here are some additional videos on water pressure to watch: