Bathtub P-trap

Once you have access to the trap it should be easy enough. If it's an abs or pvc trap you could either cut the trap out and use a mj coupling or a regular abs/pvc glued coupling. Could it be coming from your overflow? Tighten that up first see if that helps

can you access it from below?

To me, sounds like a job and a half. Recently, I had to chip away a

It is a slab built house. I am going to need to remove a certain portion of the slab to get this done. The house is 40 years old and was apparently built without enough portland cement in the concrete mix. This is what I am told. The basic indication is: when I drain the tub, there is a small bit of water comming up through the slab at a point 6 feet away. This is not good, I know. I believe that the extent of this is confined to the bathroom. There are a number of reasons I think this, and I will discuss later if anyone is interested. Thanks, Roidy

Also, upon re-reading my post from earlier this morning, I should foreswear posting before I've had my 2nd cup of joe. Soarry. :) Roidy

Im suprised there is not an access panel on an adjoining wall oposite the plumbing, I would open the wall behind the tub, then its easy. An access is necessary, it could be the shower head, valves, pipe , overflow, drain or trap. It could also be simply cacked tile grout, tub caulking or the where the valves, overflow, shower head enter the bath room. You might have a simple issue, seal the tub area first then open the adjoining wall to prove what is actualy leaking. I have an apt, and usualy its a simple issue. When you finish, make an access panel you can remove easily.

This sounds like a circumstance for an invention. I have in mind a plastic sleeve that snakes down the drain, then hardens into an impermeable inner pipe...

Im suprised there is not an access panel on an adjoining wall oposite the plumbing, I would open the wall behind the tub, then its easy. An access is necessary, it could be the shower head, valves, pipe , overflow, drain or trap. It could also be simply cacked tile grout, tub caulking or the where the valves, overflow, shower head enter the bath room. You might have a simple issue, seal the tub area first then open the adjoining wall to prove what is actualy leaking. I have an apt, and usualy its a simple issue. When you finish, make an access panel you can remove easily.