Why Do Toilets Explode?

I remember GS used to complain to me about Yank toilets, and how when you flushed them, often they would have such a violent flushing mechanism that you'd end up with water on the seat. I never understood why they didn't design them so that they didn't explode everywhere. Surely this is something that toilet designers think about? I can't imagine there's an active demand from customers along the lines of 'No, unless it just goes KABOOM I can't be certain that it will never block'.

Anyways, I had reason recently to reflect on the hubris of this in the context of Chesterton's Fence. As Megan McArdle described it:

In the matter of reforming things, as distinct from deforming them, there is one plain and simple principle; a principle which will probably be called a paradox. There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, "I don't see the use of this; let us clear it away." To which the more intelligent type of reformer will do well to answer: "If you don't see the use of it, I certainly won't let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it."

This paradox rests on the most elementary common sense. The gate or fence did not grow there. It was not set up by somnambulists who built it in their sleep. It is highly improbable that it was put there by escaped lunatics who were for some reason loose in the street. Some person had some reason for thinking it would be a good thing for somebody. And until we know what the reason was, we really cannot judge whether the reason was reasonable. It is extremely probable that we have overlooked some whole aspect of the question, if something set up by human beings like ourselves seems to be entirely meaningless and mysterious. There are reformers who get over this difficulty by assuming that all their fathers were fools; but if that be so, we can only say that folly appears to be a hereditary disease. But the truth is that nobody has any business to destroy a social institution until he has really seen it as an historical institution. If he knows how it arose, and what purposes it was supposed to serve, he may really be able to say that they were bad purposes, that they have since become bad purposes, or that they are purposes which are no longer served. But if he simply stares at the thing as a senseless monstrosity that has somehow sprung up in his path, it is he and not the traditionalist who is suffering from an illusion.

(Her article is about the so-called tax loophole for hedge fund managers that Democrats wanted to close, and is well worth reading, but that's another story).

Anyway, I wish I could tell you that I had reflected unprompted on possible reasons that toilets might be so violent and figured it out, but this is not the case.

Instead, I had observed a semi-exploding toilet on the fifth floor of a building one day. For some reason I had cause later in the day to be on the eighth floor of the same building, and the toilet was considerably more quiet. Same building, same toilet, different effect.

And suddenly it was obvious - water pressure! I imagine that it probably is quite an engineering challenge to have exactly the same water pressure at every floor of an eight-storey building, particularly if the pipe system is somewhat old. In order to get acceptable pressure everywhere, the simplest setup is just to have pressure that's slightly too high on the lower floors and slightly too low on the higher floors. Hence the fifth floor toilet explodes a bit, and the eighth is less powerful.

I made a mental note to check this - when there's a toilet with a violent flushing mechanism, I'm going to take note of what floor I'm on, and how many floors the building has. We'll see how well this hypothesis holds up.

But in the mean time, until you understand why toilets explode, you may want to hold off on demanding that they be fixed.