Home & Garden Columns

About the House: A Few Tips on the Dangers of Excess Water Pressure

By Matt Cantor
Friday August 18, 2006

Pressurizing the entire municipal water system is not an easy matter. I’m sure glad I don’t have to do it. Everyone’s bound to be unhappy. If you’re down in the flats or close to a pumping station, you’re pressure is going to be very high. If you’re waaaaay up at the top of the hills, it’s going to be much lower. We pump up the system to a pressure that will make sure that the person furthest from the pump will still have enough pressure to get a decent shower, even when her darned husband flushes the toilet (If I’ve told that man one time, I’ve told him…). 

Given this scenario, it’s inevitable that some of us are going to end up with very high pressure in the interest of other getting enough (like the rich guy at the top of the hill!). One of the reasons that this is such an important issue for homeowners is that high pressure leads to leaks and these can be major. One of the most common leaks occurs at washing machine hoses. According to one source, washing machine hose breakages cause over $100 million worth of damage each year. Coming home to a flood in your home caused by the breakage in a $10 part is both unnecessary and traumatic. I’m no statistician but I’ve personally met a few people who this has happened to. My friend John just told me last week that this happened to his house a few weeks ago while he was out of town and it’s been devastating. If the leak occurs in the upstairs of a two- or three-story house, it can do a tremendous amount of damage. 

An easy way to help prevent this tragedy is to install metal-woven “no-burst” hoses on the back of your washing machine. They can manage much higher pressure and are far less likely to burst in response to high pressure.  

One can also use these same metal-jacketed hoses on the hose connections below fixtures such as toilets and sinks. Many of these are currently made of plastic with machine-crimped metal fittings at either end. A man named “Jonny” makes these for you and usually starts getting primed for partyin’ (if you catch my drift) early on Friday to get in the mood for his big night out. He runs the crimping machine and he’s probably made a few of those hoses for your house. Jonny’s hoses are cheaper, but I’m going for the metal ones. 

Just in case the higher pressure decides to cause a leak inside the washing machine or the water heater, I’d suggest adding a pan with a drain below these devices, especially if they’re higher up than the basement. I’ve mentioned these before in a different context but it bears repeating. 

Another thing that can be done to decrease the likelihood of leakage in the case of higher pressure is to install a pressure reducing valve on the entire house. This is particularly important if the pressure at your house is above 100 pounds per square inch (PSI). I’ve seen houses where the pressure was as high as 160 PSI and the likelihood of leakage is far higher in such cases because the water is pressing so hard on every hose and length of pipe and inside every appliance that it’s just a matter of time before something bursts. Even when pipes don’t burst, slow leaks are more common and more copious. A device of this kind cost around $100 and can be in the realm of $300-$500 to install if access isn’t too bad. 

These aren’t the only things that happen when the water pressure is high in your home. Another thing is that valves are harder to operate and quicker to wear out. This applies to all sorts of valves. 

Let’s take manual spigots for starts. When the pressure is high, it’s harder to turn the water all the way off and harder to adjust it to the pressure to the specific level that suits you. You’ll tend to wear washers out faster since you’re grinding them harshly in order to turn the water all the way off. You may find yourself replacing washers every few years in such a setting.  

Several types of machines, including dishwashers and clothes washers, have automatic electrically controlled water valves that operate several times during every wash cycle. When the pressure is very high, these tend to slam open every time they’re operated, gradually wearing them out and making quite a bit of noise. On occasion, I’ve been in a house and hear the bang of the washing machine every time a cycle started and then discovered that the pressure was quite high. A whole-house pressure-reducing valve is the solution in these cases and might help save your machines from costly repairs or premature replacement due to high water pressure. 

Beyond that noise maker, there is the very common water hammering that we’ve all heard. This is most commonly heard when a faucet is shut off. This sounds like the pipes are banging against something and can be quite noisy and unpleasant, especially if it’s the middle of the night and someone’s trying to sleep. 

Water hammering can be lessened by lowering house pressure but can also be addressed in a couple of other ways. One way is to install air chambers on the top ends of two or more pipes so that air becomes trapped at the top of these lengths of piping. The air is more easily compressed than water (lower density) and acts as a spring or cushion every time the pressure in the pipe changes rapidly (when you open, or more likely, shut a valve rapidly). There are also fancier ones available that can be pumped up with air from a compressor. Water hammering can also be lessened by the installation of an adequate number of pipe straps. When piping isn’t adequately strapped in place, it’s more free to jump around as pressures change (again, mostly from rapidly turning off the water). It’s easy to add straps wherever there is access to the pipes, such as in a basement so this is a good place to begin. 

Some final thoughts on this issue should be devoted to old vs. new piping. If you have really old and obstructed piping, it may be the high pressure that’s making a shower possible. So this issue, like many is more complex than first meets the eye. Nonetheless, I don’t really recommend this set of choices. If you’ve been coping with old galvanized piping that’s so filled in with mineral encrustment that it take 20 minutes for the toilet to refill, you may want to replace that old piping with copper. If you have copper, don’t be afraid of much lower pressures. I swear that I’ve measured houses at less than 30 PSI and found the showers to just gush, even when a toilet was flushed. Higher pressure isn’t the answer to adequate flow, pipe volume is. Nonetheless, if you’re coping with very old and sluggish piping, keep in mind that despite the poor flow, high pressure can still cause leaks and floods. 

Now this is not a dangerous matter and we’re just talking about money, comfort and possible water damage but, hey, if you can afford it, reducing the effects of high water pressure might offer you a better night’s sleep in more ways than one.