Sump pump for shower drain to garage gray water tank

[bornplaydie]

I am planning a wet bath behind the drivers seat in a promaster. I am considering a gray tank inside the garage for a few reasons. I would need a sump pump (like the ones used for a boat shower drain) to pump the shower drain water into the gray tank. The sink water can drain by gravity. I was planning on wiring the power for the sump pump and the shower room light to the same switch for convenience. Does anyone have any experience with this design, and can you tell me how it worked out?

 

[DannyB1954]

You can shop for boat bilge pump. Some come with an automatic switch. One issue with these is they do not pump the water completely.
There will be a half inch or so of water sitting in the container. All the bacteria washed off of you can grow there causing an odor.

 

[crofter]

Why not mount the black tank on top of the back axle, made for it and will be large enough to pass inspection at the LTVA.
-crofter