Originally Posted by Titus
For the shower the design is poor. Need to have front down for the water on the floor to get to the drain but if the front is down the water will pool behind the toilet on the toilet ledge.
I find that on my 2012 Interstate, the best drainage for the shower AND the galley sink is to have the passenger side elevated slightly higher than the driver's side. For Grand Tours, it would be the reverse because the wet bath is on the driver's side.
A handy hint, before dumping the black tank, use the handheld shower head to top off the black tank with HOT water by running the shower into the toilet. The hot water helps soften the solids before they can reach the macerator* pump.
Another handy hint, you can use automotive spray wax (I use Turtle Wax Ice) on the walls of your wet bath to make it easier to clean. Since the wet bath isn't really exposed to sunlight, a coat of wax should last a full camping season before needing to be reapplied. In fact, if you start with a clean, dry toilet bowl, you can use the same trick to make it easier to keep the toilet clean, too.
*Macerator is actually a misnomer. It's really a masticator
pump even though no one calls it that. "Macerate" means "soften by soaking." On the other hand, "masticate" means "chew" or "grind" and that's what the pump actually does.