So why do toilets swirl the way the direction they do?

OK so any true SD fan knows it’s not due to the Coriolis effect

So why do toilets swirl one way in the northern hemishpere and the opposite in the southern hemisphere?

If I went to Austrailia and stole one of their toilets and broght it back here, would it still work the same way? (I’m guessing it would)

If it’s the manufactures design why would they make two different type of toilets like this? wouldn’t it be more cost effective just to make all the toilets swirl one way?

Please excuse my messed up tittle. I think you get the jist though.

They don’t , as any real true SD fan would know :slight_smile: As the article you linked to clearly says, “The boring truth is that water drains every which way no matter what hemisphere you’re in”.

Well I think toilets are sort of forced to spin one way or another, I doubt on such a small scale the Coriolis effect would play much of a role. But where it does come in is hurricanes and typhoons - when you have such a large mass of clouds the ones near the equator will spin slower (or is it faster?) than the ones further north or south, which leads to the spinning you see.

OK I don’t think I’m making myself clear. I get that the Coriolis effect takes no part in which way toilets swirl. I also get that are designed to spin a certain way.

What I don’t get is why are all the toilets in the northern hemishpere designed to spin one way while all the toilets in the southern hemisphere spin the other?

Or do they not spin opposite of each other? I’ve been led to believe they do. I wouldn’t know for sure being that I’ve never been outside the US or Mexico.

The standard Australian toilet doesn’t swirl like the US models. Indeed, many Australians believe that the first few toilets they come across in the US are broken - they’re really quite unfamiliar. Ours have a much smaller puddle at the bottom and there is no directional inlet underwater. The water just gushes down from under the rim.

They aren’t. It’s not illegal in anywhere I can think of to sell a toilet that drains the “wrong way”.

I order for this question to be answered you must first establish that toilets do spin in opposite directions in either hemisphere. You haven’t done this.

The spin, or lack of one, is entirely due to the design of the toilet.

Probably because the designers designed them that way.

Most of the toilets sold in the USA & Canada come from just a few manufacturers (mainly American Standard, Crane, Eljer, & Kohler). There are probably only 2-3 actual engineering designers at each company, so maybe a dozen people altogether who make these decisions. And they probably design them to flush in the same direction – I imagine that makes it simpler for the factory to make them.

Also, there is nothing in the design that would make them flush differently in a different hemisphere. If the Kohler Argentina plant used a toilet design from the Wisconsin home office, it would flush in the same direction as one built in Wisconsin.

Off we go to Uncle Cecil’s.

samclem moderator, GQ

What in the world makes you think that this is the case? It’s not.

BRITISH Tv did a small segment on this subject many years ago. It depends on which part of the equator your on, North or South, Right or Left.


Actually, no. No, it doesn’t. A reasonably good explanation of why the Coriolis effect doesn’t influence the swirl in toilets is contained in the link SHAKES gave in his first post.

I would be interested, however, if you could dig out more information on the TV segment you saw. It’s always good to know who’s responsible for propagating misinformation.

There’s lots of sources of misinformation on this. We vacationed in Kenya, before I became as involved with Cecil’s columns as I have become. there was a spot where the tour crossed the equator, and they had a big yellow line painted across the road. (It’s not a black line, as globes would cause you to believe, but yellow.) There was a guy there with a bucket, demonstrating how the water drained counter-clockwise when he was four or five yards north of the equator, clockwise when he was four or five yards south of the equator, and drained straight (neither clockwise nor counter-clockwise) when he stood on the equator. We were impressed, took photos, and gave him money.

I since understand that it must have been a trick, and that he controlled the flow. I’ll need to watch the video again someday in hopes of learning how it was done.

Meanwhile, I can attest that I was in Buenos Aires and the toilets that I used (at least, when I was thinking about it) flushed counter-clockwise, same as in the U.S.

My guess is that most toilets flush in the same direction because, deep down inside, there are only a handful of toilet manufacturers in any given country, and they probably all conform to a standard so that plumbers know where to put which pipe. I have also seen toilets as remarked above that just flush “down” with no particular spiral to them.

I cannot claim to have closely examined the construction or flushing of many of the world’s toilets. (I do have a life, y’know.) But from a purely physics standpoint, any water-processing system can move water in a certain spiral deliberately, that is, with a nozzle or bowl shape, or accidentally.

If a toilet was designed to rapidly move water downward and was not intentionally designed to direct its swirl, it is still possible to have a swirl, since it is a chaotic system. Chaos and instability can cause large effects from extremely small actions. This has often been tagged the “butterfly effect,” since a butterfly in Brazil might flap its wings, knocking a bug off a leaf, causing a frog to gobble the bug and fall off the log, frightening a bird to take flight and the flock to follow, causing more air movement, etc., tilting an unstable weather pattern just enough to, when propogated thru larger, unstable systems, cause hurricanes in Florida. At least in theory.

An simple example of an unstable system would be a pencil balanced on its tip. Which way will it fall? Just the slightest breeze or tap in any direction will produce a drastic effect – a falling pencil in that direction.

Also see chaos theory.

The influence of the coriolis effect on toilet flows is entirely too small to be of any consequence, as Cecil has said. Especially within only a few feet of the Equator.

Dex, I suspect your equatorial trickster gave the water in the bucket a small push in the desired direction. Try this with a drain. If the bucket/sink is truly neutral, you can induce an initial cw or ccw swirl which will then continue of its own accord.

I wasn’t aware that you could be right or left of the equator.

Actually, Musicat, a pencil balanced on its point is not a chaotic system, and I’m pretty sure that neither is a draining tub. Yes, it will only take a small disturbance to tip over the pencil, but once you know the direction of that small disturbance, you know which way the pencil will fall. Likewise, with the tub, if you measure the angular momentum of the water before draining, you’ll know even before you pull the plug which way the water will swirl. The pencil is unstable, and the swirl of the water will be magnified by conservation of angular momentum, but neither instability nor a magnified effect are necessarily chaotic.

Weather systems are, in fact, chaotic, and you don’t even need the bug, leaf, or frog. This means that not only can a butterfly ultimately cause a hurricane, it could also ultimately prevent a hurricane which otherwise would have formed. Without knowing the motions of the butterfly (and everything else in the system) to infinite precision, you can’t predict anything about the final state of the system.

Of course. But even when knowing the motions of the butterfly to considerable precision, the tinest factor can cause (or prevent) a larger, later action, leading to a highly-unpredictable system from the start.

Theoretically, perhaps, if we could know ALL the factors, we could predict ALL the outcomes. That may be more theoretical than practical.

Consider the motion of three mutually-orbiting bodies, often used as an example of a chaotic system. After sufficient revolutions, you will find that the tiniest nudge in a much earlier revolution caused such a magnified action in a later one as to make the orbits totally unpredictable over time. At least within the bounds of present computational power.

Granted, a pencil balanced in its point is unstable, but not chaotic, all by itself. But in a typical room, with uncertain and possibly teeny-tiny air currents and other motions (table vibration, sound waves, etc.) the action of the falling pencil might be extremely difficult to predict from random events. I would call that near-chaotic.

Meanwhile, back at the toilet – which way will the water rotate? A lot depends on the tiniest actions at the start. The smallest (possibly imperceptible in the case of Dex’s Equator bucket trick) initial action can result in a definite CW or CCW motion that continues indefinitely.

(And the bug/leaf/frog illustration was only an attempt to explain how a butterfly’s wings might lead to larger events thru increasing, repetitive or magnified smaller events.)

Unless, of course, the butterfly in question is the Papilio tempestae, or Quantum Weather Butterfly. An undistinguished yellow colour, with mandelbrot patterns on its wings. The wings are a little more jagged than one might expect, since the edgers are infinite. [See Terry Pratchet’s writings for more info]

I believe he is referring to being right or left of the East or West pole. :slight_smile: