Pipes hum when water is off, no PRV valve

[threekidhouse]

Our pipes have been humming. It happens at various times, usually when no water is running or the water had just recently been run. It happens at least 3 times during the night when everyone is asleep. I usually get up, flush the toilet, and it stops. Had the city water out and they checked the water pressure at the main and at our house spigot, 80 at main, 88 at house. We have no PRV valve that we can see. Any ideas on next step? TIA

 

[Reach4]

You should get your own pressure gauge with a maximum reading (tattletale) hand. You can get one with a garden hose thread.

Your next step would be PRV and expansion tank.

 

[Sponsor]

 

[Terry]

Do you have an icemaker?
They will sometimes refill during the night.
Also check to see if you have leaking flappers on any toilets.

 

[Jadnashua]

Many utility companies are installing check valves at or near their meters (or in it) to protect the water supply from accidental contamination emanating from an individual homeowner as part of ongoing safety updates and maintenance. So, even if you do not have a PRV, you may still have a closed system and require a expansion tank (it's code in some places for that reason). The only way for the pressure to be higher at your house verses the main is if your house is way downhill (about 0.43#/foot) from where they tested it, or if it is a closed system and you had thermal expansion with no place for it to go.

FWIW, code says water pressure should be 80psi or less, so maybe first, an expansion tank, monitor your pressure and if that doesn't' resolve it, add a PRV.

 

[hj]

Do you have a water softener, and how did your house pressure increase over the city pressure? Is your house down in a valley below the street?