How to stop urinal splashback, according to physicists
Fluid physicists filmed urine splash in slow motion. The fix isn’t aim or pressure, it’s angle. Here’s what the BYU Splash Lab and the 2025 urinal redesign found.
The cleaner knows. The cleaner always knows. Some of what lands on the floor of a men’s room never went near the floor on purpose: it bounced. And because this is science, someone has filmed it in slow motion.
The Splash Lab
In 2013 Randy Hurd and Tadd Truscott’s team at Brigham Young University built a model with a 3D-printed nozzle, fired coloured liquid at urinal-like surfaces and recorded it with high-speed cameras. They presented the results at the American Physical Society’s fluid dynamics meeting.
The headline finding: angle matters most. A stream hitting a surface head-on breaks up and splashes back. A stream meeting the surface at a shallow, glancing angle mostly runs down it. How hard or how much you go mattered less than where the stream meets the porcelain.
What that means in practice
Hurd’s own advice, as reported at the time:
- Stand closer. Distance gives the stream time to break into droplets, and droplets splash.
- Aim at the side wall, not straight at the back. A glancing blow beats a direct hit.
- Aim low and avoid the water (or the drain cake) where you can.
This is also why the famous Schiphol fly sits where it does: a target in a good spot quietly fixes your angle for you.
The urinal that fights back
In 2025 Hurd, now at Weber State University, published a redesign with Zhao Pan’s group at the University of Waterloo in PNAS Nexus. Their two prototypes, Cornucopia for standing users and Nautilus for wheelchair users, are shaped so the stream always meets the surface at a shallow angle. In tests, splashback dropped to around 1.4% of what a typical urinal produces.
The team estimates that more than a million litres of urine end up on the floors of US public restrooms every day. The designs are still prototypes, so for now the fix is up to you.
The etiquette part
Splashing is the one urinal sin that outlives you leaving the room. The next man stands in it. The cleaner mops it. Stand close, mind the angle, and if you missed, own it with a paper towel.
Quick answers
What is the best way to avoid splashback at a urinal?
Stand closer and aim so the stream hits the urinal wall at a shallow, glancing angle rather than straight on. Angle matters more than stream size or speed.
Are there urinals designed to stop splashing?
Yes. In 2025 researchers published two prototypes, Cornucopia and Nautilus, that cut splashback to a tiny fraction of a typical urinal. They are still lab prototypes.
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