This has been happening for a few months. When the water is first turned on it comes out at very high pressure, and then after a few seconds returns to normal pressure. I’ve never had a problem with low water pressure in this house, or any other plumbing problems.
It sounds like there might be air in the pipes at first, and then it settles down. Turning on the sink the water initially is very powerful and hisses, then it is normal. Flushing the toilet occasionally causes an air-hiss sound like some of those air assisted low-flow toilets. It is not an air assisted low flow toilet. At the start of a cycle the washer typically makes a few bangs as the water comes on in pulses. Now it starts with such a loud noise I thought the washer was broken, and then it settled down to the normal pulses.
Any ideas about what can cause this problem? Is it of the “call a plumber now, so you don’t have to call one at 6am on Christmas” class? Or the “if it bothers you call somebody, otherwise don’t worry about it” class?
Check to see if you have an expansion tank. It is often near your hot water heater.
It may not be pressurized right, or may be reaching the end of its life. I would guess that it has either clogged up so is no longer doing its job, or it has somehow lost pressurization, so no longer doing its job.
Replacing it is easy enough, I did my own, and they cost less than $100.
Or call a plumber if you are not comfortable with it, but it is usually attached with a screw fitting, rather than a soldered one. Literally took me 15 minutes.
Probably look at getting it fixed sooner rather than later. At some point, if it gets bad enough, it will start leaking and spraying water all over your basement. It’s also possible that the water hammer may harm other pipes in the house.
But it’s probably not urgent, can probably wait till after the holidays, but I wouldn’t suggest waiting till summer.
Thanks for the tip. I don’t have an expansion tank, though. The water comes in, I think up through the floor in the basement. That pipe Ts and half goes to the sprinklers, which are currently turned off. The other half goes up into the basement ceiling, and I assume all of the fixtures in the house.
On the part that goes up into the ceiling is some sort of directional devices, which an image search suggests is a pressure regulator. Either that or a brake master cylinder, in which case I have more problems than hissing water.
I don’t know much about plumbing, but weird water pressure sounds like a possible failure mode for a pressure regulator. It’s a minimum of 10 years old, but probably 50 years old.
Here is the device and close up. The close up is not out of focus, it is genuinely blurry, which is why I think it’s probably closer to 50 years old, than 10.
The house is a split level, so there are four floors. The problem exists in the laundry room, which is a half level above the basement; in the kitchen, a half level above that, and directly above the basement; and in the master bath, another half level up. It probably exists other places, but that’s where I use water the most.
Once the pressure has been relieved, the air purged, or whatever, it will take some time to come back. I’m not sure exactly how long, but it does happen multiple times per day.
It is also possible that your water district recently installed backflow preventers. They would have done so at the street, so they may not have told you about this.
Without the preventers, as the pressure in your pipes increased, that would just push out to the street, using the whole system as an expansion tank. With them, your house is now isolated, and so your hot water tank is acting as the expansion tank, which it’s not really designed to do.
In that case, installing an expansion tank may solve your problems. For installing a new one, I would definitely recommend getting a professional involved.
It may be your regulator, but I don’t think so, in my Not a Plumber but have done lots of home repairs opinion. If anything, the pressure surges may be what is damaging the regulator.
Sounds like there could be air locked somewhere in the system - air is much more compressible than water, so when the outlets are turned off, a pocket of air in a pipe will compress and store energy that will be released to the water when you open it up again.
If the air is trapped in a part of the pipe where it goes up and over something, the water can still flow past that and the air might just bubble back to the high spot.
Sometimes turning everything on full blast, and flushing the toilets at the same time, can generate enough flow to carry the air out of the pipes.
That is my concern. I can fix a toilet, but I just don’t know enough about plumbing to have a sense of failure modes, or which symptoms are dangerous, and which are harmless.
Nothing has been installed on the water lines near my house, but if it was even one street over it could happen without me ever knowing.
It could be that there is air in the water main that is working it’s way out though your plumbing. They may have been working on a pipe section to cause this. Your just the lucky home that gets the air. If so it may subside but yes open the taps at full to try to flush it.
The device looks like a check valve/pressure regulator. It has a bleeder valve on top but I don’t think that will be very helpful for you in it’s location. The suggestion to get an expansion tank is a good one. You might need some float valves in the system to release air also. First thing though is try to bleed the air out of your system. Just open all the faucets in the house and flush the toilets for a while. Repeat every day for several days and see if it makes a difference. Without valves somewhere in the system to release air it could take a while
I’m starting to question whether it is air in the lines. Looking at guides for flushing them, it talks about sputtering, and I don’t get that. I know exactly what that is like, as the plumbing in my old condo was poorly designed, and it was not possible to turn off the water to individual units, but only the whole building. So multiple times per year I would get the sputtering as the pipes refilled.
What I get now isn’t sputtering, but extra high pressure. Imagine turning on a faucet to full blast, then backing off to halfway. That’s what I get, except that the “halfway” pressure is what always used to be full pressure.
I’ll give the flushing a try, as it seems easy enough. Some of the guides say to turn off the supply, then open all the faucets and let the water drain, then open the supply again and let it run for 15 minutes. Others say to just open all the faucets and let it run for 15 minutes.
Is there any chance it’s the anti-scalding valve misbehaving in one of the showers? I vaguely remember some issue discussed where that value caused weird plumbing problems, but I don’t remember the details.
That is a PRV (pressure reducing valve.). It’s purpose is to keep your house’s water pipes from becoming over pressurized and to keep the water pressure in the house constant.
Normally what should happen is as follows. If the supply pressure is lets say 80 psi and the PRV set to 60 PSI. With all valves in the house closed the PRV will be closed and the house water pressure will be 60 psi. When a valve is opened the house pressure will begin to drop and the PRV will open to maintain close to 60 psi.
Over time they can get scaled up and not open and close properly. It may act slowly. If the PRV did not close properly as the pressure built when the last valve was shut off the pressure can build to supply pressure (80 psi). Then the valve will slowly close, but house pressure is now 80 PSI. When you open the faucet the pressure will be high and dropping fast at some point below 60 psi the valve will begin to open and pressure will build back up to 60 psi where over time the PRV will stablize at 60 PSI.
Or the valve may be sccaled up to the point that the inside movable parts don not move. Sjut the water off and the pressure begins to build until supply pressure is reached. You open one faucet and bang the pressure dropps. The valve will be part way open so the pressure will depend on how much water is flowing through it. 1 faucet open it might approach 60 PSI. But if someone is taking a shower at the same time as the dishwasher is running and the clothes washer is running the pressure may drop below 60 PSI depending on just how far the valve is open.
There is a simple test. The hardware store should have a pressure guage that can be connected to a hose bib or garden hose. Connect the pressure guage to a facuet and turn the facuet on. NOte the pressure. Then turn on 1 faucet and see what happens. Does the pressure drop and then return to a constant value with the water running or just dropps. Then increase the water flow and make the same notes. Then turn the water off watching the guage and see how long it takes to approach the starting pressure.
I live in SAn Jose California and our water is so hard I always advise chewing it before swollowing. My PRV does not completely shut off and the pressure builds to 80 PSI. With a flow it dropps to 60 PSI and holds. I am not getting complete closing on the PRV. But I will bet 95% of teh PRVs in this county do not work properly. I made the mistake of rebuilding the ones in one of the building I use to work in. They lasted about as long as a new valve would before starting to hang up. 6 months. It was a complete waste of time, parts, and money.