Two weekends ago I opened up the drywall and replaced the valve on a bathtub. After opening the wall I was able to see that the plumber who installed the tub also apparently had trouble installing drains correctly.
Apparently the tub has been draining into the ground under the bathtub since it was installed around 7 years ago with the top of the trap probably acting as a siphon only when the hole in the slab was sufficiently full.
I've since replaced the drain and everything seems watertight now. A week later, the musty smell of stagnant water is gone but the soil is still quite damp.
So my question: how dry should I aim to get the dirt before closing up the hole in the drywall that I've been working through? And how to do in the tight confines under the bathtub?
I am concerned that once I close the wall up, any moisture will have no way to escape, so I'm also wondering if I should treat the area with something to disinfect and discourage any mold growth before sealing it up.