[CliffMc]

Hi, I have a strange one. When I run water in my bathroom vanity, sometimes I what sounds like water dripping, it doesn't happen a 100% of the time. Seems like when it is cold and I run hot water it is louder. Here is the funny part, I don't see any water marks in the vanity. I followed the pipes into the basement (panel ceiling), and there are no watermarks there either. Sometimes the noise occurs when I run the water, and sometimes when I open the drain.

Could it just be a pipe expanding and rubbing on something???

I know this is a vague, but don't know how else to explain it.

Does anyone have any thoughts?

Thanks,

 

[lenaitch]

Most likely expansion/contraction in either a supply or drain line if is bound too tightly to a joists, etc. or run through too-small a hole. Plastic will usually do it more than metal. we had it in the main bathroom drain that ran down the wall of the den - drove me nuts.