This is a real tough one. I have a very slow drip leak coming out of my shower into the cellar. This has been happening with no one using the shower as well as when it is being used. I took a look and it seems that there is a drip line going down the side of a pvc pipe that seems to lead up to the shower head and then goes into the drainage system. I can't seem to stop this bothersome leak. It's pretty near impossible to get up in behind the tub since it was sealed off by the contractor some years ago. Any suggestions? Thanks!