Every time we use the hot water for our sink or shower in our upstairs bathroom, a banging noise occurs. The noise sounds like a pipe is hitting against the wall from the inside. What could this be and should we be concerned?The noise has been there since we bought the house 2 years ago, so we're use to it, but I get worried sometimes that it could be a pipe and that it might burst. Does anyone know what exactly this noise is, and should we take action?

Could be water hammer. Does it just make one big thump when you close off a faucet or valve quickly? That would be water hammer causing the pipe to actually jump and bump into a stud or some other lumber.

Describe the noise for us. One large bang? Lotsa little bangs? A rattle? Please be more specific. Regards, Tom