water.....

Did you try tightening the shower drain flange?

You mean that plastic piece of junk, yeah it's tight. Cut a hole in the underbelly and joy of joys, looks like there's a holding tank that'll need to drop before I can get to the drain.

Bummer, hope it eases up for 'ya.

Look on the other side of the wall from the shower. In my trailer I had crawled into the storage area under the rear bed (don't ask) and there was a panel in the wall with a screw holding it up. I removed the screw and panel and the underside of the tub and drain were right there. Maybe your trailer has a similar setup.

Thanks for the advice & comiseration, shower is in the back corner of the trailer, so there's no (existing) access panel. I'm thinking about making one though......problem with that is the vanity is tight to the shower pan on the drain side. I'm just hoping that there's not too much damage to the framing/floor.

Water is a really good thing when it is located where you want it, and in the state you want it in (solid vs liquid, etc.). But it sure turns bad in a hurry when those factors are otherwise than what you need them to be.