Following success in the Bay Area and a German city, SEPTA will test a liquid-repellant coating in the coming months. And yes, they hear your human waste complaints.

Updated at 1:20 p.m.

Could our days of encountering sad, smelly puddles on the way to the sub be numbered? Probably not, but SEPTA is exploring a new public urination prevention approach.

SEPTA spokesman Andrew Busch tells Billy Penn that the agency is planning to test liquid-repellant coating this fall. “It’s imminent. It’s coming soon,” Busch adds later, saying trials are slated to begin in a couple weeks.

This development follows Bay Area Rapid Transit installing anti-pee coating in 80 of its elevators last month. Busch explained via email that where the trial evaluations will be conducted is “still being determined.” So, there’s no telling yet if SEPTA will test the coating in any of the transit system’s elevators. Busch could tell us that the paint will be “same as or similar to what was done in San Francisco (and I believe Hamburg, Germany) with the superhydrophobic coating.”

In 2015, a coalition of local businesses in Hamburg’s St. Pauli neighborhood made news around the world, when they installed a pee wall. St. Pauli is a popular night-life and red light district. Public urination had long been a problem, despite local fines, so the neighborhood organization coated the area’s “most frequented walls.” They placed signage on some, but not all, to warn folks that if they planned to pee there, their plans could, um, backfire.

San Francisco was inspired. St. Pauli’s pee walls made headlines in March of that year; by that July, San Francisco sprayed down nine of their own, quickly installing more in the months to follow. Busch tells Billy Penn that SEPTA will be using the same product employed in both San Francisco and Hamburg: Ultra-Ever Dry. This paint, per reports, isn’t all that expensive. According to the San Francisco Chronicle, the coating (installation included) only set the city back “a couple hundred dollars for each wall.”

BART’s elevator initiative was much more costly though. The agency didn’t simply spray the floors, they first replaced the floorboards on 80 elevators entirely. The lucky elevators were also equipped with a bacteria-fighting misting system that fires once an hour. This project cost almost $2 million.

Current cleaning protocols in SEPTA elevators vary some. Darryl Wade, director of stations operations, says the elevators along the Market-Frankford and Broad Street lines are given “a routine basic” clean “at least twice daily.” SEPTA contracts elevator cleaning in the downtown Regional Rail stations out to Center City District. CCD tends to them four times a day, says Dell Williams, SEPTA assistant director of Center City stations. Complaints aren’t that common— Williams says once or twice a month in these RR concourses, Wade says once or twice a week for the subway lines. Williams added that most complaints are related to “human waste.”

How does a spray-on paint make liquid splash back at you? What does superhydrophobic mean? Laurie Winkless, a physicist-slash-science writer for Forbes, provides this explanation:

“A hydrophilic (literally, water-loving) surface is one that water sticks to easily, so a droplet on it will look a bit like a flat-ish dome. Drop a little water on your desk, or a nearby plate, and you’ll see it spread out and flatten. On a hydrophobic (water-fearing) surface, a droplet of water will stay roughly spherical. The classic image used for this kind of surface is the lotus leaf, which remains matte and clean, while water on its surface gathers into jewel-like blobs. Basically, hydrophobic materials are difficult (sometimes, impossible) to wet, and that’s the key to producing something that’s water – or pee! – repellent.”

In San Francisco, it seems like the walls are working… mostly? Neighborhood news site Mission Local enlisted a volunteer to pee on walls to test them out on camera. (In the video, there is lots of urine, but no, the volunteer isn’t exposed.) The coating was largely ineffective in their report. Mark Shaw, the CEO of UltraTech, the company that manufactures Ultra-Ever Dry, told the news site that graffiti could be curbing the product’s effects. Officials from the SF Department of Public Works have said the Mission is a trouble area, but that the vast majority of walls were splashing as expected.