In the streets of Hamburg, Germany, a new form of urban deterrent is turning public urination into an instant lesson in cause and effect. Known as “anti-pee paint,” this specialized nano-coating creates a superhydrophobic surface, repelling liquids so completely that anything touching it slides off with remarkable force. The result? Anyone attempting to relieve themselves on a treated wall experiences an immediate and unforgettable splash-back. The technology borrows from nature, mimicking the microscopic structure of a lotus leaf. Tiny ridges and air pockets prevent any liquid from adhering, meaning walls remain clean while offenders get an eye-opening consequence — all without the need for confrontation, fines, or patrols. It’s an ingenious blend of physics and human psychology: the paint doesn’t punish with authority, it punishes with instant feedback. First popularized in Hamburg’s St. Pauli district in 2015, this approach has since been trialed in other cities like London and San Francisco. While the coating is costly, city authorities note significant savings on cleaning and maintenance, and a marked decrease in repeat offenses. Beyond hygiene, it’s a striking example of how urban design and material science can work together to shape behavior. For engineers, urban planners, and city residents, anti-pee paint is both a marvel of nano-engineering and a lesson in poetic justice. The streets stay cleaner, the message is immediate, and the offender leaves with a story they won’t soon forget.

If there was a toilet right there, do you think they would still choose the wall?
If they would still choose the wall, do you think the paint is going to deter them?
How will people even know that the paint is piss-splashing paint?
Will people not immediately change their piss angle as soon as they get splash back?
They have walked out of a club with a toilet five minutes ago. How frequently do you want there to be toilets?
The idea is that by putting the risk in people's minds it'll be a deterrent, or else by giving people a natural consequence (and also protecting the wall from being stained with piss) it'll deter repeat offenders.
Oh, you mean the gross, overcrowded toilet that is typical of clubs? Weird that they didn't want to use that. I wonder why that could be?
/sarcasm
No, just a regular toilet in a public establishment. I don't know anyone who's thinking "this toilet is gross, so I'll piss in the fucking street". I guarantee you noone is wiping down the street with anti bacterial spray.
Toilets can get busy, yet queuing for one is very normal. Have you noticed that no-one sees the queue and goes on the corner?
That's because this is caused by drunk people failing to plan ahead and then when caught short not having any inhibitions.