Chinook RV

We have a 2005 Concourse, and we THINK the bathroom sink drain may go in the black tank, just based on sounds. But not sure. Does anyone know for sure? If it does, I'm sad. 15 gal is kinda small to start with, for a black tank, for old people. But add the water from washing your hands after each flush and that adds up!
I guess I'd try to find some container to fit it and dump either in kitchen sink or outside.
First we need to know if it actually does.

Only thing that goes to the black tank is the toilet. Everything else go to the gray tank. There is a diagram of the plumbing in the manual. You can see a copy on the Reference section.

Please try not to dump gray water on the outside. Others may misunderstand what you are doing, and spread rumors about wrong procedure that mislead others.

Thanks chin_k That's good to know. Never thought about others thinking I was doing something not good by throwing water outside.
Thanks again for the info, I'll have to check out the manuals on here.