I have a 2d floor bathtub with a shower. Whenever someone takes a bath, water leaks down to the 1st floor bathroom. It was so bad I had to have the ceiling in the downstairs bathroom replaced. This only happens when someone takes a bath, not when someone uses the shower. I recently had a plumber replace the assembly that controls the bathtub drain because we thought that's what was causing the leak. He ran the shower for a good 5 minutes and no water appeared downstairs. At the time, I didn't realize that the leak was apprent only when someone used the tub. Well, someone took a bath and the leak started again. I was told that while they were taking a bath, the water was leaking from the tub. How can that be? Help!