Coriolis Effect: Do toilets flush differently in the Southern Hemisphere?

by Chris on January 8, 2011

Do toilets in the Southern Hemisphere really drain differently than toilets in the Northern Hemisphere? Don and I test out the Coriolis effect on a toilet

coriolis effect

File this under juvenile. When I called my husband from Peru on my first trip to South America, he asked me a question that I had often wondered about but never witnessed firsthand. Do the toilets in the Southern Hemisphere really flush the opposite way from the Northern Hemisphere?

I was willing to give it a try. Trouble was, I had forgotten which way the toilet drained back home in Seattle. So while we were on the phone, Don went into the bathroom and flushed the (empty, of course) toilet. “Counter clockwise!” he reported.

Lima´s turn for this impromptu science experiment. I went into the well-appointed bathroom of the Liberator Hotel and gave it a flush. It bubbled and for a second I worried that the hotel had a LEED-sanctioned toilet that drained in a special way. But no. Down the water swirled……Clockwise!

Turns out there´s a fancy physics term often ascribed the phenomenon: the Coriolis effect. Moving objects appear to deflect differently when they are viewed from a rotating reference frame (in this case, the Earth). It´s most often applied to meteorology, where winds and ocean currents have been observed to act differently north and south of the Equator.

(I am so bad at explaining science – for a more complete description, check out the Wikipedia entry on Coriolis)

Alas, it seems that Coriolis isn´t the actual reason behind my Lima toilet behaving differently than the Seattle drain back home. has an interesting article that states that the basins and drains installed in your bathroom have more to do with the direction of the swirl instead of centrifugal forces.

Oh well. It was fun to do the experiment anyway. For my next trick, I´ll put Don´s hand in a bowl of water while he´s sleeping, just to see what happens. 😉

| Chris Gray Faust is a veteran journalist, travel expert, social media butterfly - and editrix of this site. Like what you read? Check out her writing, editing and social media services.

{ 7 comments… read them below or add one }

Christine January 9, 2011 at 9:08 am

You guys are hilarious. And this reminds me of this Simpsons episode:


The NVR Guys January 9, 2011 at 7:28 pm

I thought the exact same thing.


Kevin June 2, 2012 at 9:19 am

The only reason I decided to look this up was that Simpson’s episode! My friend’s daughter is visiting Chile which provided some impetus too.


Chris June 3, 2012 at 8:00 pm

Kevin – Too funny. I still need to see the ep.


Poi January 17, 2011 at 11:38 am

haha I love it – these are the sort of posts I love to read! aka fun.


Jahanzeb May 25, 2011 at 7:17 am

Love how you posted the answer. Helped me in my Science Project for sure!


Chris May 27, 2011 at 9:02 am

@Jahanzeb – Always happy to help with science projects….when I can 🙂


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