Most self-cleaning public toilets use a combination of timers and weight sensors to make sure the space gets thoroughly cleaned between visits -- without soaking any innocent visitors. The process works something like this: You check to make sure the toilet is unoccupied and ready for use, then open the door to begin your time. After you've used the toilet, you leave the booth, at which point the door automatically locks and the magic begins.
With some self-cleaning toilets, a robotic arm comes out of the wall behind the seat and scrubs the surface. On others, the seat itself swivels through two complete 360-degree turns, passing through a squeegee-like tool at the back that cleans the seat on the first pass and swipes away extra water on the second. And in some of the newest self-cleaning toilets, a section of wall folds down over the toilet in much the same way that a trunk lid hinges down and closes over the back of a car. The toilet is then sanitized with either a disinfectant solution or a burst of ultraviolet light.
The entire process takes anywhere from 40 seconds to 2 minutes, and if everything is working as it should, the next visitor to step into one of these state-of-the-art stalls will find a wet floor, a clean smell and sparkling surfaces without a handle or a knob in sight. And while a wet floor isn't normally something you hope for in a public restroom, in this case it's a good thing, because it means that the floor has been sanitized with disinfectant cleaner. Rest assured: As long as you leave the stall when you're finished -- and you don't attempt to dash in as the patron before you steps out (and before the self-cleaning cycle has a chance to run) -- there shouldn't be any risk of getting an unexpected shower.
We love a spotless and sanitary public restroom as much as the next person, but we have a bigger question: Why can't we have self-cleaning toilets at home?