It is a commonly held misconception that toilet water always drains counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere because of the Coriolis force an acceleration imparted by the Earth's rotation. The influence of the Coriolis force on spin direction is real, but it is generally only observable on very large scales, such as trade winds and hurricanes. The affect the Coriolis force has on a toilet bowl is much too small to actually see in a flushing toilet but that doesn't mean that it doesn't exist.

As boring as it may sound, the direction that toilet bowl water swirls at the equator has more to do with the toilet's manufacturer than it does any physics phenomena. Does water drain counterclockwise or clockwise in your house? Share your experience in comments. Let`s conduct research together.