New urinal designs reduce splashback by optimizing surface angles, improving hygiene, and enhancing accessibility.
A urinal engineered to minimize urine splashback, both onto the user and the surrounding floor, would significantly enhance sanitation, maintain cleaner restroom environments, and improve the overall user experience.
Urinal design has remained largely unchanged for over a century. The model famously reimagined as art by Marcel Duchamp in his 1917 Dada piece Fountain still closely resembles many of the fixtures found in public restrooms today.
Traditional urinals often result in urine splashing outside the intended area, onto floors and, more unpleasantly, onto users themselves. This not only creates unsanitary conditions and increases the risk of disease transmission but also leads to higher maintenance and cleaning costs.
A high-speed video depicting the tests used to measure the critical angle. Three impinging angles are shown (left to right: 90◦,60◦, and 30◦, respectively). Credit: Thurairajah et al.
Engineering a Cleaner Alternative
Zhao Pan, Kaveeshan Thurairajah, and colleagues calculated that when the flow of urine impinges on the surface of the fixture at 30◦ or less, splashback is greatly reduced.
Experimental results confirmed this. The authors then designed urinals by solving differential equations, dubbed Cornucopia and Nautilus, which have impinging angles at or below 30◦ across their entire area. The Nautilus design has an additional advantage: it fits a range of urination heights, making it easier for children and people who use wheelchairs to use.
According to the authors, if the 56 million urinals in public restrooms in the US were replaced with the Nautilus, it would prevent one million liters of urine from splashing onto the floor each day.
Reference: “Splash-free urinals for global sustainability and accessibility: Design through physics and differential equations” by Kaveeshan Thurairajah, Xianyu (Mabel) Song, J D Zhu, Mia Shi, Ethan A Barlow, Randy C Hurd and Zhao Pan, 8 April 2025, PNAS Nexus.
DOI: 10.1093/pnasnexus/pgaf087
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4 Comments
Urinals don’t splash if you aim right.
A few years ago I read an article about a urinal that the manufacturer determined the optimal aim point for, and then put the image of a fly there in the ceramic glaze.
OK, an article I can get in front of!
Wow. Cornucopia looks a bit risky though especially if you’re vertically challenged like me.