A newly developed toilet coating could save 70 billion litres of water a day, scientists believe.
The slippery surface needs only half the water to get the job done.
Scientists have discovered bacteria repelling spray-on “sludge” that keeps toilets clean and reduces the amount of water needed to flush.
Globally more than 141 billion litres of water are used to flush toilets every day.
Professor Tak-Sing Wong at Penn State University said: “With millions of global citizens experiencing water scarcity, what if that amount could be reduced by 50 per cent?
“Our team has developed a robust bio-inspired, liquid, sludge and bacteria-repellent coating that can essentially make a toilet self-cleaning.”
The new method – liquid-entrenched smooth surface (LESS), is a two-step spray that lasts up to 500 flushes before needing to be reapplied.
It first covers the ceramic bowl in an “extremely smooth” liquid repellent and then adds a layer of lubricant to make the slope even slippier.
Prof Wong said: “When it dries, the first spray grows molecules that look like little hairs, with a diameter of about 1,000,000 times thinner than a human’s.
“The second spray infuses a thin layer of lubricant around those nanoscopic “hairs” to create a super-slippery surface.”
The researchers tested the spray with synthetic faecal matter and found it left the bowl “spotLESS”.
Prof Wong said: “When we put that coating on a toilet in the lab and dump synthetic faecal matter on it, it (the synthetic faecal matter) just completely slides down and nothing sticks to it (the toilet).”
The team hopes their loo-spray will make waterless toilets and urinals more pleasant, while also allowing any saved water to be redirected towards drought-stricken areas.
Prof Wong said: “Poop sticking to the toilet is not only unpleasant to users, but it also presents serious health concerns.
“If a waterless toilet or urinal used the LESS coating these types of fixtures would be more appealing and safer for widespread use.”
The coating takes just five minutes to set, unlike other surface-sprays which can take hours.
Prof Wong said: “Our goal is to bring impactful technology to the market so everyone can benefit.
“To maximise the impact of our coating technology, we need to get it out of the lab.”
The researchers set up a company called spotLESS Materials, which aims to bring their slippery spray to market and has already attracted a lot of interest.
Prof Wong said: “As a researcher in an academic setting, my goal is to invent things that everyone can benefit from.
“I see this culture being amplified through entrepreneurship, and I’m excited to contribute.”
The findings were published in the Nature Sustainability journal.