I had feared it, but I’ve now verified: Water is leaking through my bathtub walls. The walls are tile on drywall. One area looked kind of messed up before I moved in, caved in slightly. The grout is kind of cracked and is (fairly poorly) caulked over in some spots.
I had seen some moisture on the pipes and in the carpet in the basement. This morning, I saw wet spots in the floor joists and sub-floor and actual dripping. So it was finally time to take off the access panel.
The access panel probably hadn’t been opened in a while. The seams were partly painted over, and the panel was quite difficult to get out. A piece of trim is now quite loose after all the prying.
The drywall behind the tile is bowed and crumbling. There are some spots of mold back there. I vacuumed and will spray some clorox in there, but I no doubt will have a much larger project looming. I will have to decide if I just want to toss on a bunch of caulk, regrout, or tear the wall down and rebuild. I was hoping I wouldn’t need to do anything like the latter for a while.