If you're wondering why bidets are so common in Italy, you might attribute their seemingly huge popularity to the fact that many Italians take cleanliness, including personal hygiene, very seriously.

But this isn’t just a cultural norm. The people responsible for Italy’s building regulations apparently consider bidets non-negotiable, too; since 1975, every Italian home has been required by law to have one. The regulations state that "at least one bathroom in each house must have the following: toilet, bidet, bathtub or shower, sink." This means that Italian new home builders can only sign off properties as safe for habitation once these features are installed. Homeowners who don’t install all of these features may have problems when it comes time to sell their home.

Italian law also stipulates that bidets should maintain a minimum distance from other bathroom fixtures: bidets should be at least 20 centimeters from toilets and bathtubs, and at least 10 centimeters from sinks.