When I bought my Desert Fox 21SW toy hauler, I installed a dump station ay my house.
The master bathroom was at the side of my house where the RV parking stall was. There was a cleanout under the house, since that was the upper end of the plumbing drain line. I put a threaded coupler in place of the cleanout cap, installed a wye with another threaded coupler, put the cap there (so I still had a cleanout) then on the other leg of the wye, I ran a new drain line out through one of the foundation (crawl space) vents.
I used it a lot. That was at my house in Spanaway, WA
