We have a leak from our bathtub that leaks into the kitchen below only when I give my son a bath. Usually it starts when he is in the bathtub, but last time it didn't start until after he was out and the water was completely drained (it happened right after all the water drained out). It only happens when my son takes a bath, we don't shower in there. I have tried to duplicate it without my son in the tub and I can't get the leak to happen. (I also supervise him to make sure he is not splashing). I have dumped water down the overflow and that didn't create a leak either. Our tub is a one piece plastic tub, no tile.

I have taken out the drain and tried to reseal it with plumbers putty and then around the drain with caulk and that didn't work. I then took the drain back out and shoved a hose in the pipe and turned it on to see if it was the pipe, and it didn't leak. From that test, I assume it must be the drain or a crack in the tub. Doe anyone have any suggestions on what I might do? When you take the basket out there is only a spacer in between the pipe and the tub. If you take the spacer out, it appears to be a free floating pipe. (hopefully that helps you know what kind of set up I have). I can also take out the lighting in the kitchen and see the pipes under the tub from there and the leak comes down from the drain pipe.

Any help would be wonderful!

Stand in the tub and let someone else look for a crack. Orfill the tub and use food coloring and it will expose the crack after a short time.