[terry and jo]

OK. A "harmonic" is something that occurs "away from" the original source. It is noticeable in electronics and sounds.

Our "water harmonic" occurs in the vicinity of the shower faucet when we run water (usually hot) at either the kitchen or bathroom sink. It is a humming sound and if I'm in the bedroom, it sounds like a big horse fly is buzzing around in one of our cabinets or drawers. (Ours is a side bathroom unit, so our shower shares a wall with the bedroom.)

So, have I got a vent problem or something?

Or, have I got a mental problem?

Either answer could be right.

Terry