Water pipe humming sound.
Why is there a loud humming sound every five minutes in my main water pipe near the main shut off valve. Note this happens when there's no water running in the house? I do have a pressure reducing valve. Also my friend next door hears the noise to. I turned off his water main in his house and the noise stopped in my house, but when I turned my main water supply valve off and his back on he still could here the noise in his house. What do you make of that?
I have here that this noise can possible be caused by a leaky valve in a neighbors house, is that a fact? This is the first time that I have ever hered of a humming noise in a plumbing system. A friend also said that it could be coming from the city water main.