Originally Posted by Sailmonkey
This works for us, and it's fun to flush with a sink full of water that you've just shaved in.
That's not good for a toilet pump...among other reasons, it strips lubrication off the rubber parts
in it and can "gum up" the pump. It also defeats the whole purpose of teeing the head inlet line into the sink drain, 'cuz all the stuff that goes down a sink drain--hair, soap scum, body oils dirt etc is the same stuff that can make a shower sump
stink if you don't clean it often. Flush your shaving cream and all your other gray water out of sink drain, not into the toilet.