On our initial run, I had the gray water overflow into my basement compartment with my brand new 2017 SportsCoach
When it first happened, I thought the fresh water tank was leaking, confirmed later that it was the gray tank overflow. Stupid thing just empties right into the basement area where the city water hookup and waste gates are located. A lot of the water ends up on top of the fresh water tank when it is not full and just sits until you move (top indented) located below the gray and black tanks. When I left my site, the water ends up poring out of the bottom metal frame and looks real bad. This happened to me twice after waiting for the monitor to show "full".
I have since learned not to wait until the monitor says "full" as by then its too late. I now drain the gray water at two-thirds full and haven't had any issue since.
As Noted: the gray water did not back-up into the shower (older models) as this and some other threads suggest its suppose to do. FR says the gray tank overflow is on top of the gray tank and is not part of the vent pipe system and the newer models. Dealer states this is not a leak and is normal!
So, has anyone tried to attach a drain line from this overflow point at the top of the tank and direct it down and out of the bottom of the coach so that no water ends up in the basement compartment? If so, can you provide direction?
It looks like to access the top of the waste tanks one has to remove the water panel just in front of them. Not too many screws but a lot of water connections to work around.