re: Plumber baws: diy double vanity question

Being that you can't have fall from both sinks due to entering a Tee, I see what you're saying. May always be some water in that lateral section due to that...But as long as you have P traps under both fixtures, I don't see a problem. Unless a hair ball or something forms and just pushes back and forth without exiting the Tee.

I dunno...Not a plumber either, just my thoughts.