If you’ve ever used a public restroom in the United States, you’ve probably noticed it: toilet seats that are open at the front, leaving a distinctive U-shape. For years, this quirk was seen as an American oddity. Now, however, the design is popping up in France too—in airports, train stations, and restaurants.

At first glance, it looks like a matter of style or cost-saving. But the truth is more surprising: it’s not just design, it’s regulation.

A Rule Written Into Law

In the U.S., open-front toilet seats have been the norm since the 1950s, when the Uniform Plumbing Code made them mandatory in all public restrooms—unless disposable seat covers are provided.

The reasoning wasn’t aesthetic. It was hygiene. By cutting out the most exposed part of the seat, the design reduces the chance of direct contact with splashes, makes cleaning faster, and limits the spread of bacteria in high-traffic spaces.

What Science Says