The short answer: yes — every flush launches an invisible “toilet plume” of tiny water droplets that can shoot up to 1.5 metres (about 5 feet) into the air within seconds, and those aerosols can carry bacteria and viruses onto nearby surfaces like the floor, sink and even your toothbrush. Scientists have now filmed this happening with lasers. The good news: for a healthy household using its own toilet, the everyday risk is modest and easily managed. It matters most in shared and public toilets and when someone is ill. Closing the lid helps — but, surprisingly, recent research shows it doesn’t fully seal the plume in, so the most effective step is simply keeping the toilet and the area around it clean.
“Toilet plume” sounds like an urban myth, but it’s a real, measured phenomenon — and in 2022 a team of engineers made it visible for the first time using high-powered lasers, with genuinely startling results. This guide explains what the plume actually is, whether it really spreads germs, the honest and slightly counter-intuitive evidence on closing the lid, how worried you should actually be, and the practical steps that make the biggest difference. Sources are linked at the end.
How we researched this: the findings below draw on the University of Colorado Boulder laser-visualisation study published in Scientific Reports and surface-contamination research in the American Journal of Infection Control. Full references are at the bottom.
What is a toilet plume?
A toilet plume is the cloud of tiny airborne droplets — an aerosol — thrown up by the turbulence of a flush. The water crashing around the bowl breaks into microscopic droplets small enough to float in the air and drift, carrying with them whatever is in the bowl. Because the droplets are invisible, most people have no idea it’s happening.
In 2022, engineers at the University of Colorado Boulder used bright green lasers and high-speed cameras to photograph the plume from a lidless commercial toilet for the first time [1]. What they measured was dramatic:
- Droplets were ejected upwards at speeds of up to 6.6 feet per second (about 2 metres per second).
- The plume rose as high as 5 feet (1.5 m) above the bowl within about eight seconds.
- Smaller particles lingered in the air, drifting and settling across the room rather than falling straight back down.
That study used a lidless public-style toilet, which is the worst case — but it made the mechanism undeniable. Every flush really does launch a cloud into the air, and in a lidless toilet there’s nothing to stop it.
Does the plume actually spread germs?
Yes — the plume can carry pathogens, and this is well established. If the bowl contains bacteria or viruses (from an infected person’s waste, for example), the aerosol droplets can carry them up and outward, depositing them on surfaces up to about five feet away — floors, walls, the cistern, the sink, taps and anything else nearby. Studies detect the settled contamination on those surfaces after flushing [2].
The germs of most concern are the ones spread through faeces and vomit — above all norovirus, the winter-vomiting bug, which is highly infectious and can be aerosolised by flushing. Other gut bacteria such as E. coli, Salmonella, Shigella and C. difficile can travel the same way. Crucially, the plume only spreads what’s actually in the bowl — so a healthy person flushing their own toilet is launching mostly harmless droplets, whereas the same flush during a stomach illness can spread something genuinely infectious around the room.
The toothbrush problem
Here’s the detail that makes people wince: if your toothbrush sits on the counter or in a holder within a few feet of the toilet, it’s inside the plume’s landing zone. Aerosol droplets from flushing can settle on the bristles you then put in your mouth. It’s not a guaranteed illness — most of the time the droplets are harmless — but it’s an easy risk to remove. Keep toothbrushes in a closed cupboard or drawer, or at least as far from the toilet as your bathroom allows, and close the lid before flushing. This one habit is worth more than any amount of worrying.
Does closing the lid actually help?
This is where the science gets more nuanced than the popular advice suggests — and it’s worth being honest about. “Close the lid before you flush” is sensible, intuitive, and does reduce the direct upward spray. But it is not the perfect seal people assume.
- Earlier studies found that closing the lid reduced the aerosolisation of bacteria and the contamination of nearby surfaces — the basis for the standard advice.
- More recent research complicates that. A 2023 study in the American Journal of Infection Control found that closing the lid before flushing did not significantly reduce contamination of surrounding surfaces — because aerosols still escape through the gap between the bowl and the seat/lid [2].
- Follow-up work on that “air gap” confirmed droplets and viral particles leak out of the sides even with the lid down, with more escaping as the gap gets bigger [3].
So closing the lid is still worth doing — it blocks the fastest, most direct jet and is a sensible default, especially near toothbrushes — but don’t treat it as a force field. The plume finds its way out around the edges. That’s why the most effective control turns out to be something else entirely.
What actually works best: keeping the bowl clean
The same 2023 research tested what really cuts contamination — and the winner was straightforward hygiene. Cleaning the bowl with a disinfectant and brush reduced viral contamination on the toilet by more than 99.99%, and cut contamination on the brush itself by around 97.6% [2]. In other words, the biggest lever isn’t trapping the plume — it’s reducing how much pathogen is in the bowl to be aerosolised in the first place, and disinfecting the surfaces around the toilet.
Practical version: a toilet (and bathroom) that’s regularly cleaned and disinfected launches far less of concern with each flush, and any droplets that land on cleaned surfaces meet far fewer germs. Routine cleaning quietly does more than any single flushing trick. For the full method, see our guide to deep-cleaning a bathroom.
How worried should you actually be?
It’s worth keeping perspective. The plume is real and it can carry germs — but “can spread pathogens” is not the same as “will make you ill.” A few things put the risk in context:
- In a healthy household, your own toilet mostly aerosolises your own harmless microbes. The everyday risk is low, and there’s no need to be anxious about every flush.
- The risk rises sharply when someone is ill, particularly with a diarrhoea-and-vomiting bug like norovirus — then the plume can genuinely spread infection around the bathroom and to the next user.
- Shared and public toilets are the higher-risk setting: many users, often no lid, and surfaces touched by many hands. Good hand-washing afterwards matters far more here than the plume itself.
So the sensible response isn’t fear — it’s a few cheap habits that cut the risk to near-nothing, and extra care during illness.
What to do about it
| Habit | Why it helps |
|---|---|
| Close the lid before flushing | Blocks the fastest direct spray (even if not a perfect seal) |
| Keep toothbrushes in a cupboard/drawer | Removes them from the plume’s landing zone |
| Clean & disinfect the toilet regularly | The single most effective step — cuts bowl and surface contamination >99% [2] |
| Wipe nearby surfaces (sink, handles, lid) | Where plume droplets settle |
| Ventilate the bathroom | Clears lingering aerosol faster |
| Extra care during illness | Lid down, disinfect after each use, own towel |
| Wash hands properly afterwards | Breaks the main route germs actually reach you |
Myths vs facts
| Myth | What the evidence says |
|---|---|
| “Toilet plume is a myth.” | It’s real and now directly filmed — droplets reach ~5 ft at up to 6.6 ft/s [1]. |
| “Closing the lid completely stops it.” | It helps but doesn’t seal it — aerosols escape the bowl-seat gap [2][3]. |
| “Every flush is a health hazard.” | Only if the bowl holds pathogens — a healthy home‘s flush is mostly harmless. |
| “There’s nothing you can do.” | Regular disinfecting cuts contamination >99%; it’s the biggest lever [2]. |
| “A toothbrush by the toilet is fine.” | It sits in the plume’s landing zone — move it into a cupboard. |
The bottom line
The toilet plume is real, measurable and can carry germs — but it’s not something to lose sleep over in a healthy home. Every flush throws up an invisible aerosol that can reach five feet and settle on nearby surfaces, so a few sensible habits are worth adopting: close the lid, keep toothbrushes out of the firing line, ventilate, and — most importantly — keep the toilet and bathroom regularly cleaned and disinfected, which the research shows is by far the most effective control. Save the extra vigilance for when it genuinely matters: shared and public toilets, and any time someone in the house has a stomach bug. Do that, and the plume becomes a non-issue.
Frequently asked questions
Is toilet plume real?
Yes. It’s a well-documented phenomenon, and in 2022 University of Colorado Boulder engineers used lasers to film it directly for the first time. They measured droplets shooting up at up to 6.6 feet per second and the plume rising as high as five feet above the bowl. Every flush genuinely launches an invisible aerosol into the air.
Can you catch something from a toilet plume?
It’s possible but not inevitable. The plume only spreads what’s in the bowl, so a healthy person’s flush is mostly harmless. The real risk is when the bowl contains pathogens — for example during a norovirus or other stomach illness — when the aerosol can spread infection to surfaces and the next user. Good cleaning and hand-washing keep the risk low.
Does closing the toilet lid stop germs spreading?
It reduces the direct spray but doesn’t fully stop it. Recent research found aerosols still escape through the gap between the bowl and the seat, so closing the lid alone didn’t significantly cut surface contamination. It’s still a sensible habit — especially near toothbrushes — but regular disinfecting of the toilet is far more effective.
How far does the toilet plume travel?
The visualised plume rose about five feet (1.5 metres) above the bowl within seconds, and smaller particles then drifted and settled across the room. Contamination has been detected on surfaces up to around five feet from the toilet — which is why nearby items like sinks, handles and toothbrushes are in range.
Should I keep my toothbrush away from the toilet?
Yes — it’s an easy, worthwhile precaution. A toothbrush within a few feet of the toilet sits in the plume’s landing zone, so aerosol droplets can settle on the bristles. Store toothbrushes in a closed cabinet or drawer, keep them as far from the toilet as possible, and close the lid before flushing.
What’s the most effective way to reduce the risk?
Regular cleaning and disinfecting of the toilet and surrounding surfaces. In testing, disinfecting the bowl with a brush cut viral contamination by more than 99.99%. Reducing what’s in the bowl to be aerosolised, and keeping nearby surfaces clean, does more than trying to trap the plume itself.
Is toilet plume worse in public bathrooms?
Generally yes. Public toilets often have no lid, are used by many people, and have powerful commercial flushes that generate bigger plumes — which is exactly what the CU Boulder study filmed. The most important protection in a public bathroom is thorough hand-washing afterwards, since hands are the main way germs actually reach you.
Does flushing spread norovirus?
It can. Norovirus is highly infectious, present in vomit and faeces, and can be aerosolised by flushing, so a plume during a norovirus illness is a genuine way it spreads around a bathroom. During any diarrhoea-and-vomiting illness, close the lid, disinfect the toilet after each use, ventilate, and wash hands rigorously.
Does ventilation help with toilet plume?
Yes, it helps clear lingering aerosol faster. Running an extractor fan or opening a window reduces how long fine droplets stay suspended in the air after a flush. It’s a useful supporting measure alongside closing the lid and keeping the toilet clean, particularly in a small, enclosed bathroom.
Do I really need to worry about this at home?
Not much, day to day. In a healthy household the plume mostly carries harmless microbes, and simple habits — lid down, toothbrushes away, regular cleaning — reduce the small risk to near zero. Save the extra care for when someone is unwell or you’re using shared facilities. It’s a reason to keep good habits, not a reason to be anxious.
Related reading: does vinegar actually disinfect? and antibacterial vs plain soap: does it work better?
References
- Crimaldi J.P. et al. “Commercial toilets emit energetic and rapidly spreading aerosol plumes” (laser visualisation study). Scientific Reports / University of Colorado Boulder, 2022. colorado.edu
- “Impacts of lid closure during toilet flushing and of toilet bowl cleaning on viral contamination of surfaces in United States restrooms.” American Journal of Infection Control, 2023. ajicjournal.org
- “Study on the air gap effect when closing the toilet lid on droplet and pathogen escape from flushing.” American Journal of Infection Control, 2025. ajicjournal.org
This article summarises published research for general information and isn’t medical advice; during infectious illness follow NHS guidance on hygiene and cleaning.
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