pipe noises

[Tom Robertson]

Several times a day we hear a humming coming from the pipes. At first we thought it was the furnace coming on (that type of sound), but it is not. If I turn on a faucet or flush a toilet it will quit for a while, but it always comes back. This occurs when no water is being used in the house. Can anyone help?

[jadnashua]

Do you have a pressure reduction valve in the house? These typicallyhave a check valve in them. Also, so water meters have them, and some municipalities use them as well. Any of these will create a closed system in your house - water will come in, but not out. Now, that protects the rest of the neighborhood from potential contamination that might creep infrom your house, but it creates its own problems within yours. When the hot water heater heats the incoming cold water, the water expands. Sometimes, this increase in pressure hitting up on the check valve, if it leaks a little, will make some noise as it leaks back through that check valve. Now, this may not be what is happening at all.

At a plumbing supply house, and maybe a big box store, you can buy a pressure gauge that will screw onto a hose bib. A place in the house that would work if you don't want to go out in the cold would be the washing machine connection. Check your pressure. Take a bath, check it again. Then, watch it and see if it goes up as the hot water heater recovers. If the sound happens when the hot water heater is running, thatmay be your problem. If it isn't, somebody else will probably have some ideas.

[Gary Swart]

A water pressure gauge is an inexpensive item to put into your water supply and I find it nice to know exactly what my pressure is. Rather than the hose bib, I opted to plumb mine in to the main line. It to a tee, male adapter and bushing to reduce the 3/4 supply line to 1/4 theaded pipe connection on the gauge, but it was very easy to do. If you have a closed system and have to install an expansion tank, it would be a natural to do the gauge at that time.

[plumber1]

Check the toilets real good. If there is a slight leak through the toilet it also can cause a humming sound.
When the noise is present go to each and and shut off the supply valve or take the lid off and lift up on the float rod or float mechanism to see if that stops the noise immediately. If it's a toilet, it's probably just one of them.

[hj]

Two things commonly cause the noise, a bad toilet fill valve or a hose attached to an outside faucet that has not been turned off at the valve.