Thanks in advance if you can help. My upstairs neighbor prefers to bathe in the tub instead of shower. I noticed water damage in my bathroom ceiling. A plumber was called. Cut holes in the ceiling below my neighbor's tub where the leak was occurring. We filled his tub, but no leak. Tested the overflow, but nothing. Left the holes to try to determine the leak. Finally, I saw water dripping down the drain pipe. Figured the seal around his bath tub drain had deteriorated. Plumber came and replaced the drain. Epoxied the drain to seal. Regroated around the tub. It still leaks!! Leaking doesn't occur during fill or drain of the water into/out of the tub. We can fill the tub and leave it, but no leak. It doesn't leak when he takes a shower. Only when the tub is filled and he's sitting in the tub. As soon as he pulls the plug to drain, dripping stops. He weighs about 160. Water isn't going into the overflow.