Its called the Coriolis Force Did you really check?...because your answer should also be clockwise:toetap05:
i know.. thats why i'm all tripped out over this! i swear it goes counter clockwise.. my bathroom is a vortex into australia!
actually it depends on the design of the toilet too...some are cast to force a vortex a certain way...maybe yours was made in China....its best to check by filling the sink...and then pulling the plug out and dropping some food coloring....or watching when the bathtub drains. That was one of my favourite Simpsons episodes