Two basic tub questions

[Stuka]

I opened the small access panel below the tub and there was standing water...I guess that's the top of the grey tank beneath the tub? Looks like it is several inches below the floor. Any idea where that is likely to be coming from? I dried it and will check it again 1. next time I use the tub and 2. next time it rains.

And, the tub itself, seems to have a piece of flash trim that attaches to the walls, and is sealed to the wall. There is a small gap between the flashing and the tub, but in pictures of tubs online, it appears there is a small lip on the tub that tucks in behind the flashing, so as long as the flashing does not leak from the top, it's good. Does that sound right? Because standing in the tub, the fiberglass tub flexes a little and pulls away from the bottom of the flashing...

A lot of how this camper is built is a mystery to me, as far as drains and how it is designed not to collect water and rot the flooring.

[chuckster57]

If the tub drains into the tank in your picture then yes it is the gray water tank. As far as the standing water on top of it? That can come from a number of sources. I would have someone run the kitchen faucet while you watch the tank top. Then run the bath sink, and then the tub. If you don't see any standing water then you need to fill the tank FULL.

The shower pan/tub is designed with that lip to go behind whatever is on the wall to prevent leaks. I would probably include using the shower head along the entire length of that seam during my tests. I hope you find the leak easily and it's not a complicated fix. Feel free to post back if you have any questions.