Tapping in wall

[Mike Richards]

Hi,
Need some input.
2 story home built in 2005 while running tub on 2nd floor a tapping can be heard in wall on 1st floor where drain line goes down to slab. No water leaks and only happens with tub running and draining. noise stops after water is shut off and drain is empty.

Thanks
Mike Richards

[Jerry Peck]

Expansion and/or contraction of the supply and/or drain piping, which is rubbing against the supports and/or framing as it expands and/or contracts.

Does it do it more with hot water or cold water, or did you only run both?

Usually, it happens more with hot water as the hot water expands the hot supply piping and the drain piping more than cold water does.

[Mike Richards]

Thanks Jerry,

ran both hot and cold together.

[Rick Cantrell]

Since you said there it is leak, I believe there is more to it than what Jerry describes.