[Carl n Susan]

The grey tanks do not have any fresh water input lines. The only input is from the various drains (sink, shower, etc.). At least that is the way they are built. I think it is time to remove the panel around the convenience center, and maybe the back wall of the passthru compartment and see where the various lines got to. As a previous;ly owned coach there could have been modifications made to the "standard" plumbing.