The smell isn’t the only difference between public toilets and the one in your house. In case you haven’t noticed, public toilet seats are almost always U-shaped, whereas personal toilets have round or oval-shaped seats. What’s up with that?
The International Association of Plumbing and Mechanical Officials (IAPMO) has required public restrooms to have “open front toilet seats” since the 1950s. The seemingly bizarre requirement appeared for the first time in IAPMO’s 1955 American Standard National Plumbing Code, and again in its updated guidelines, the Uniform Plumbing Code, published in 1973.
Why? It’s actually all about hygiene, in particular, female hygiene. Lynne Simnick, senior director of code development for IAPMO, explained to Slate that the code’s original intent was to allow ladies to wipe without coming in contact with a potentially unhygienic seat.
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Even though ladies were the intended beneficiaries of the U-shaped requirement, Simnick couldn’t help but point out how men also benefit from the seating arrangement. The design “eliminates an area that could be contaminated with urine” and also “eliminates the user’s genital contact with the seat,” she noted.
According to Slate, the code doesn’t have any legal force on its own, but many city, country, and state governments do adopt it as law. All told, it currently applies to more than half the population of the U.S. and the world.
So there you have it!