[aef222]

When I turn off either shower in the house, I hear a high pitched whining noise. It stops if I turn on any other water source in the house, but then starts again when I turn it off. It only lasts about 10 minutes. What is it?

[danielnoahsmommy]

Air in the pipes

[hkstroud]

Are you on a municipal water system? Do you have a pressure regulating valve? Are you on a well system?

[aef222]

I assume I'm on a municipal system (I don't have a well). I wouldn't know where to look to see if I have a pressure regulating valve... On a friend's advice, I did try turning on every water source in the house at once, starting from the top, but that didn't help.

[ballengerb1]

I would buy a presssure gauge and fittings to attach it to the garden spigot. If your pressure is over 50 psi you need a pressure reducing valve (PRV) to bring it down or you already have a PRV that needs adjustment or replacement. The high pitched whine is temporary excessive pressure blowing past a valve seal, likely the toilet ballcock or frig ice maker.

[hkstroud]

Look for a PRV valve at the place where you turn off the water to the house. Should look something like this.

[hkstroud]

Bob
Note that the whining noise is occurring when the shower is turned off and continues for 10 minutes. I'm thinking trash in PRV as it tries to adjust pressure .

[ballengerb1]

I agree, it could be a PRV trying to reduce the pressure, or like I said, maybe another valve like a ballcock or ice maker. Something is venting the excess pressure, your thought about a PRV does make the most sense. Good call Harold.