San Francisco is about to follow up a German experiment in deterring revellers from urinating on buildings by giving them a taste of their own medicine.Â
The pilot programme will involve painting nine walls with a repellent paint that splashes urine back with almost the same force as it it hits the wall.
Mohammed Nuru, the city’s public works director, said it was all about making San Francisco smell nicer.
"We’re piloting it to see if we can discourage people from peeing at many of our hot spots," he said. "Nobody wants to smell urine."
Walls treated with the paint will have signs that read "Hold it! This wall is not a public restroom. Please respect San Francisco and seek relief in an appropriate place."
But the signs do not warn that the wall will return fire.
The "superhyperhydrophobic" coating goes by the trade name Ultra-Ever Dry, and was developed in by a Florida-based company called UltraTech International.
It works by creating a surface textured with tiny prongs that cause drops of water to hover, a phenomenon known to biologists as the "lotus leaf effect".Â
The paint repels other liquids and sludges, including oils, paint and wet concrete.
The product is expensive, at about $470 a gallon, but that has to be set against the nuisance and expense of steam-cleaning afflicted buildings.
One of these men wore clothes painted with Ultra-Ever Dry, and one didn’t (UltraTech International)
The paint was first used in the public realm in March, on Hamburg’s Reeperbahn, in the centre of the city’s St Pauli red light district.Â
The problem with public urination – "Wildpinkler" – is taken seriously in Germany, and offenders risk paying a fine of several hundred euros.Â
However, Hamburg does not have the resources to watch the 20 million visitors to its nightlife area, so the city authorities and the St Pauli Interest Community.
Walls treated with the paint were fitted with signs warning that they "pee back", and the city also made more public toilets available for those in distress.Â
Top photograph: Hamburg’s Reeperbahn, which piloted the splash-back offensive (Huhu Uet/Wikimedia Commons)
- The company has uploaded a promotional video to YouTube showing its invention in action.