Leaking Shower Problem on Upper Level Floor

This is very frustrating because I think the only way to find out where the leak is coming from is by ripping down some drywall to see the plumbing pipes. But what really is upsetting is that I don’t know where the leak is on the first floor or on the top floor. I think it is going to be a big headache. I don’t even know where all the plumbing pipes run behind the walls. Do you know if the home builder keeps the drawings of all the water pipes so I can see what I am looking at? Please can you get back to me with your thoughts? Thanks a lot for your time and I hope to hear back from you soon.

Answer: This type of problem can be very frustrating and expensive, both from a damage and a repair standpoint. The good news, from the way it sounds, is that you have no water damage. More than likely your leaking shower problem is associated with the drain pipe, rather than with the copper supply lines. The problem most likely is at the P-Trap or shower drain itself. As you have already figured out, if it was the copper supply lines, you would always observe a water leak.

The first thing I would check is to see if there is any sign of water damage to the ceiling on the lower level, specifically underneath the shower stall area. If there is, then it is a sure bet that your leaking shower problem is associated with the shower drain assembly. If no water stain is observed, it is still possible that the water is slowly leaking from the shower drain and then running along the drain pipe before it drips off of it, possibly onto the hot copper supply line. Once the water hits the supply line it could travel along it until it then drips onto the floor in the basement.

Unfortunately you may have no choice but to cut into the lower level ceiling just below the shower unit. P-traps can sometimes have a large nut that can be unscrewed to get access to the inside of the trap. One possibility is that this nut could be loose. Also the drain could be cracked and/or damaged. However before going down this route, first take off the drain strainer plate that sits at the bottom of the shower unit and check the gasket underneath it. It may not be seated well, or could be damaged. Also check the drain area for cracks or damage. With PVC shower units that have glued in shower drains this is a frequent problem. In addition, you may want to apply a bead of plumbers putty right under the rim of the drain strainer plate. Sometimes water that may be leaking around the shower drain strainer plate and drain can be eliminated this way.

If addressing the drain strainer plate does not solve your problem then you will probably have no choice but to cut into the ceiling to get access to the P-Trap and shower drain assembly. If the shower drain and/or P-trap assembly is broken contact a plumber and have them replace it. Hiring a plumber may help to minimize the amount of drywall cutting.