I live with two curious cats, so when it comes to the “lid up” or “lid down” question, in my house it’s definitely “lid down.”
Not to get too personal here, but I don’t normally lower the lid until after I’ve flushed the toilet, to avoid having to clean and disinfect the inside of the lid too often.
But I’m going to be changing that practice — starting today. Read on and you, too, will be convinced that the hygienic and health benefits of flushing with the lid down are worth the extra cleaning job.
A rocket plume of nasty germs
For a few years now, scientists have been zeroing in on the fact that standing over a toilet while you flush it isn’t a very good idea.
Their interest in airborne particles and how fast and far they travel was likely prompted by the spread of COVID-19. But when it comes to toilet water, there’s no telling what what’s in those droplets…
In 2020, scientists at the University of China found that a flushing toilet resulted in 40 percent to 60 percent of particles reaching above the toilet seat, sending some droplets nearly three feet into the air. And the microscopic particles that can contain viruses could stay airborne for over a minute.
Then, in 2021, scientists from Florida Atlantic University built on this research by setting up a particle counter at various heights next to both a toilet and a urinal in a public restroom.
“After about three hours of tests involving more than 100 flushes, we found a substantial increase in the measured aerosol levels in the ambient environment with the total number of droplets generated in each flushing test ranging up to the tens of thousands,” says Siddhartha Verma, a professor in mechanical engineering from Florida Atlantic University.
Aerosols rose as high as 3.6 feet above toilet bowls and as high as 2.3 feet above urinals during the course of the experiments and could hang around for as long as 20 seconds.
In late 2022, researchers went one step further…
They gave us a “visual” of the contaminated particles we’re breathing every time we flush our toilets.
“We had expected these aerosol particles would just sort of float up, but they came out like a rocket,” says civil and environmental engineer John Crimaldi from the University of Colorado Boulder.
Watch their 90-second video to see what they saw.
How to avoid contaminants when you flush
Now that you’ve watched the video, I’m sure it’s clear that the very best health practice is to shut that lid before you flush.
That’s easy if you’re at home, but if you’re in a public restroom, you probably won’t find lids on toilets.
In that case, the best you can do is to slide open the bolt on the stall door so you can make a speedy exit once you’ve flushed the toilet. Turn your face away from the toilet as much as you can when you flush.
At home, you may also want to consider flushing less (when it’s yellow, be mellow). That may seem unsanitary, but sources say you will spread fewer germs that way. You may end up needing to clean your toilet bowl more often, though!
Sources:
Do You Flush With The Lid Up? You Won’t After Watching This — Science Alert
Commercial toilets emit energetic and rapidly spreading aerosol plumes — Scientific Reports
CU scientists shine light on what comes up when you flush — CU Boulder Today
Disgusting Study Shows What Happens in The Air When You Flush a Public Toilet — Science Alert
Gross Toilet Flushes Really Could Spray Viral Particles in The Air, Study Finds — Science Alert