Many educated people believe that water drains counter-clockwise in the Southern Hemisphere, and clockwise in the Northern Hemisphere.
This is called the Coriolis effect. It has to do with the Earth’s rotation, and empirical evidence such as cyclone and typhoon direction.
However, it is FALSE.
Even though the Coriolis effect is valid if all other things are equal, it has so little force that things like tilt and flush location have a far greater effect.