Same thing with my previous Coachmen MH. The toilet was on the curb/passenger side of the coach, and there was a second slide valve right below there on a pipe leading to the black tank. (It SHOULD normally be open, but strange things have been known to happen with RVs.) And of course the dump valve was on the street/driver side.
2019 Thor Freedom Elite 30FE
Living The Dream in "God's Waiting Room"