Weird noise in pipes. Any suggestions?

jacopoxy · 2012-11-27T18:43:33+00:00

I hear a strange noise in my walls when I shut off running water from a fau=cet. Doesn't matter if hot or cold water. Doesn't matter which faucet or =valve (e.g. sink, shower, toilet, etc.) I would describe the noise as a gi=ant pendulum swinging back and forth, rubbing against the wall. It lasts f=or about 2 or 3 seconds. I can't imaging a pipe swinging loose like that. =I've tried cutting holes in walls to find a loose pipe, but no luck. I have= copper piping throughout.I thought this was a hammering issue. So I drained the whole house then rep=ressurized. The problem persists. My house was built in 1997.Any ideas on what this could be?Thanks,AABob