I asked this at Remodeling, but maybe you Home Repair folks can help:

We have a false wall (a knee wall? except it's about 6.5 feet high) at the end of the tub; it holds the pipes for the shower.

We had a Swanstone tub surround put in, and the fixtures changes (I don't know how much of the piping was replaced, or if they used the existing pipes and just put on the new handle & shower head).

The drywall on the end of the wall got really wet and soppy at the bottom, and there was a little damage on the side walls (the shower side is cement board, so it's firm, but the caulking between it and tub got screwed up; also wasn't applied well). But the end wall took the brunt of the damage.

It took a long time to get DH to deal w/ it, and in that time, the wall would get gradually less damp overnight, then get wetter after morning showers.

I assumed there was a really slow leak inside that wall, and that we were going to have to redo the pipes or the joints.

Finally DH removed the cabinet by that wall so we could look inside--he can't find a leak anywhere. And he can't MAKE it leak.

Most of the interior is dusty and dry. (The dust on the surface of the cold-water pipes is slightly damp, but it turns out that's likely from the condensation that builds up on those unwrapped pipes that are so close to the hot-water pipes; my FIL the pipe fitter says we should wrap the pipes to insulate, and that will eliminate this small condensation.)

So, if the condensation isn't a factor, I keep trying to figure out what could cause the drywall to be so wet.

The only thing i can think is that water that fell OUTSIDE the shower (when pre-teen DD took a long shower once) got that drywall wet, and it never dried up.

The room is well heated w/ a steam radiator, but it also doesn't have incredible ventilation. Nevertheless, towels end up dry by morning in there; it's not prone to staying steamy.

And DH and I are the other shower-takers there; we're careful not to spill outside the shower. DD doesn't shower daily, and I've checked the bathroom when she's done; there's not usually a puddle on the floor.

Could the drywall have held the moisture for several days? Maybe even weeks?

Oh, DH ran the space heater in there, blowing the hot air (it's a Vornado, so has a fan) right at the section, and it now feels dry, and for a week hasn't gotten damp again.

I'd hate to assume that there was no leak, and close it up, and find out we were wrong.

Also, if the drywall got that soggy, wouldn't it be smart to remove it? DH wants to just patch and paint; I want to remove the dry wall and reapply (which will be a bigger deal--and require hiring a handyman of some sort).

Can we dry that drywall out enough to simply patch?