Dealing With High Water Pressure

Having adequate water pressure in your home is something you take for granted. Anything less can compromise your ability to live comfortably and is flat out annoying. But, have your ever stopped to think about what too much water pressure means? You might think it’s no big deal and the firm stream of hot water in the shower feels just as much like a massage as it does a cleansing experience. However, the truth is there’s a fine line when it comes to water pressure. Too little of it leaves you wanting more and hinders your ability to clean, cook and wash. On the other hand, too much water pressure can cause some serious damage to your home and plumbing system. Below we discuss some signs of high water pressure and how to go about addressing the problem.

How to Tell if Your Water Pressure is too High

The signs should be pretty easy to detect. If you notice an abnormally heavy stream of water coming from your faucets, shower head, or your outside hose bibbs, it’s something you should look into. If you don’t address the problem right away, you risk broken pipes, high water or power bills and even catastrophic damage to the inside of your home.

How to Check Water Pressure

If you think your water pressure is too high, all you need to do is purchase a simple pressure gauge that attaches to a hose bibb. Since your house water pressure is usually the highest during the night when no one is using any water, a lazy-hand test gauge works best. Put it on a hose bibb and leave it on over night or even for a few days. The test gauge lazy-hand will then indicate the highest pressure that was reached during your absence. The recommended maximum water pressure for a home is 80 pounds per square inch (PSI). If your gauge gives you a reading of anything over 80 PSI, there’s definitely a problem.

Causes of High Water Pressure

There are a number of problems that can lead to excessive water pressure in your home. Knowing what to look for and how to address each one can make addressing the problem easier and save you money.

Faulty Pressure Regulator

Your home has a water pressure regulator that controls how much water pressure is allowed to your plumbing system from the municipal water supply. In many cases, the water pressure set by the water company in their main water lines will be set to the pressure that meets their needs of getting adequate water to fire hydrants and apartment buildings. This pressure can often exceed 150 PSI. As a result, it’s the job of your pressure regulator to reduce water pressure to the pressure as adjusted on your pressure regulator. Most pressure regulators are factory set for 45 psi but are adjustble between 10 psi and 90 psi.

Unfortunately, pressure regulators, like any man made device, will eventually fail and need to be repaired or replaced. Depending on the age of the regulator they can usually be repaired if repair parts are still available. If you test your water pressure and it’s too high, it might be time to repair or replace your regulator.

Thermal Water Expansion

Sure, the name sounds really technical. That’s because it is. But the concept really isn’t that hard to understand.

After water flows through a pressure regulator into a house plumbing system, it is stored in the pipes ready to be used when a faucet is opened. But until a faucet is opened, the plumbing system is pressurized and considered a "closed" system. It's condsidered a closed system when potable water has no way to exit the homes plumbing system until a faucet is opened. An open system allows water to be forced back into the city water main through the supply line.

When a water heater heats water it causes the water to expand because water does not compress under normal household conditions. As the water expands it increases pressure on the "closed" system known as thermal expansion. A thermal expansion tank should be installed at the water heater to receive the expanded water and keep the pressure safely under the temperature and pressure relief setting.

Not every household water heater has a thermal expansion tank installed, even though most codes require them if you have a pressure reducing valve, or other device that prevents backflow, installed on your water system that would make it a closed system.

If you notice a significant increase in your water pressure it would be a good idea to find out if your temperature and pressure relief valve (T&P valve) is opening and releasing hot water. The easy way to check this is to find the T&P valve discharge pipe located outside of the building which should be no higher than 6" above ground and are usually a copper 90° elbow pointed down with a short piece of copper on the end. T&P valve discharges cannot have threads on the end of them so no one can put a cap on them. Other approved plumbing material can be used but the outlet must not have any threads. Check and see if the ground below the outlet is wet. If it is and you don't have a thermal expansion tank, then you should consider installing one.

If you notice a significant increase in your water pressure and you have a water heater thermal expansion tank, then check to make sure it is large enough to handle your system’s demands. Larger water heaters require larger thermal expansion tanks. See our thermal expansion tank quick-sizing chart.

Water Hammer Effect

You’ve never heard of it, right? That’s because it’s another technical term that sounds complicated but can be understood pretty easily.

Simply put, the term water hammer effect describes what happens when water pressure changes so drastically that it causes a vibration of the piping due to the change of water flow when water flow is suddenly closed off by turning off a faucet, or when a pump suddenly turns off. When this happens, rushing water has the effect of a hammer on your home’s plumbing system.

In other words, when water that is moving at a high velocity through you pipes is stopped suddenly by turning off a faucet, the water hits the stop point with tremendous force and reverses direction creating waves inside the piping as the reverse direction of the water flow pushes against the original oncoming flow. These pressure waves also referred to as hydraulic shock create the vibration known as water hammer. If you hear loud or repeated banging sounds when you turn water off, you are witnessing the water hammer effect.

Water hammer shock waves can cause spikes in pressure that may exceed the working pressure of the system and over time cause damage to valves, pumps, pipes, fittings, and gasketed connections resulting in leaks.

Even though your plumbing system is designed to withstand sudden changes in water pressure when the pressure is adjusted to acceptable levels, higher than normal pressure will cause certain parts of the system to wear out sooner due to the simple opening and closing of valves (turning water on and off).

If you suspect this to be the case, you need to examine the pipes and fixtures closest to the sound right away. Left untreated, faulty parts or fixtures can rupture at a moment’s notice and cause serious damage to your plumbing system.

You should be able to locate the sound of the water hammer effect on your own, but if you’re having trouble, it’s best to call a plumbing professional to diagnose the problem and replace any faulty parts before matters get worse.

Though it’s not always as noticeable as low water pressure, excessive water pressure isn’t something you should ignore. Sure, those blistering showers and faucets that remind you of Old Faithful are great. But if your water pressure suddenly spikes to a noticeable point, it’s something you should investigate. The good news is, if you know what to look for and can perform some simple diagnostic tests, fixing the problem is often easier than you think.




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