In my house I have a vibrating/humming sound that happens Separatically . Sone times it won't happen in days and some times it goes on for hours. Its so loud it keeps me from sleeping. Just wondering if any one knows what's happenning This happens when water is not running

Next time the humming starts, turn off the stop valves under any toilets and see if the humming stops. Come back for guidance.

Harold's on to something here. See if the noise is stronger around one toilet then another? My bet is that you're going to find it in a toilet ballcock. Let me know which one and we'll go from there. Tom