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Hands-free faucets not necessarily better, say scientists


April 1, 2011

A study has shown that more bacteria are present in water dispensed from hands-free electronic-eye faucets, than in that from conventional faucets(Photo: SCA Svenska Cellulosa Aktiebolaget)

A study has shown that more bacteria are present in water dispensed from hands-free electronic-eye faucets, than in that from conventional faucets
(Photo: SCA Svenska Cellulosa Aktiebolaget)

Just three years ago, a study conducted by the University of Westminster, London, determined that the "hygenic" warm air hand dryers commonly found in public washrooms actually left users with more bacteria on their hands than if they'd simply used paper towels. Now, it seems that the good name of hands-free electronic-eye faucets is being similarly besmirched – researchers at The Johns Hopkins Hospital in Baltimore have discovered that water coming from such faucets contains more Legionella bacteria than that dispensed by conventional fixtures. Their theory is that the high-tech faucets' complex inner workings are to blame.

The hands-free faucets use a sensor to detect when a user's hands are present, at which point the water will automatically come on for a preset amount of time. Given that the whole process involves no touching of anything, it would indeed appear to be more hygienic than a system in which multiple users touch hot and cold water handles with their unwashed hands. The folks at Johns Hopkins and other U.S. hospitals obviously thought so, and proceeded to introduce the faucets in patient care and public areas over a decade ago.

When Johns Hopkins staff were testing how often their water system needed to be flushed, however, they were surprised to discover Legionella growing in 50 percent of the cultured water samples from 20 hands-free faucets, as compared to only 15 percent in samples from 20 manual faucets in the same areas. While Legionella pose little risk to healthy individuals, they can cause serious infections in people with weakened immune systems.

The water from the traditional faucets was also found to contain just half the amount of other types of bacteria.

Although the reasons for the difference are unclear, the researchers suspect that the complex valve components of the newer faucets offer more surface area and hiding places for bacteria, which remain present even after standard hospital water disinfection methods. Conventional faucets, on the other hand, have few internal parts.

Johns Hopkins has since replaced all 20 of its newest hands-free faucets with manual models, and is in the process of replacing 100 similar faucets throughout the hospital. The research team now plans on working with manufacturers of hands-free faucets, to devise new ways of building them so that they can be more easily and thoroughly cleaned.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away. All articles by Ben Coxworth

So back to filthy handles. Did they evaluate the bacterial risks with that?


Manufacturers needs to coat the insides of water pipes with either silver or one of the many antibacterial plastics available. That way when the water is not flowing, the bacteria is broken down harmlessly and safely.

Or is this too obvious?

Stuart Halliday

What a load of crap. What kind of study was this, did they test faucets from different manufacturers and from different countries? I\'m sorry but testing faucets from one hospital made by on manufacturer is not a study! Why would you publish something like this in Gizmag, Gizmag used to be my fav tech site but you guys seem to have lost your way.


The point is to get less germs on your hands afterwards - including the bit where you turn the tap on and off (or not, in the case of electric eyes) - what\'s the point of testing just 1/3rd of the problem - the water only?

Not to mention common sense - what the heck difference could it possibly make if a solenoid instead of a handscrew actuated the faucet stopper?


I have not really ever liked the hands-free faucets. To me it just presents another failure mode (lack of power, for example). Mechanical systems where the user steps on a pedal to dispense water have been available for a long time and I like those better. In the absence of one of those, a lever handle that one can shut off with an elbow after washing seems like a pretty good way to control the water without touching the fixture...

Alan Belardinelli

Frankly, good riddance to those horrid automatic faucets. They shut off suddenly when you need them, run water when you don\'t need it on (wasting it), and don\'t work when power is out. When I was in Toronto during a power outage, during an August heat wave, it was impossible to flush toilets, wash hands or anything else, or drink water, as it was all \"automatic\"= run by electricity. Having a small child (or even just a sweaty face), one needs paper towels to wipe things up... one cannot wash off a skinned knee or a wet counter someone has spit on with an automatic faucet and blowdryer (and most children are frightened of those blow dryers... cannot get my kid near one. Incredibly unhygenic, wet dirty countertops and wet hands... use your towel to shut off the handle, people, it isn\'t hard. I\'m glad to see these high tech gadgets go.

Leanne Franson

wow i saw this back to the basics

adam smolkowicz

Scientists! I wish they would just make up their minds.


\"Hands free\" faucets are fine when the user controls the flow by a pedal or other means and the temperature is neutral (not too hot or cold). Air dryers are a dumb idea as anyone who has ever needed to dry his face will tell you. The only stupider idea is those cloth dryers. Both will not last.


After 3 months of using a hands free faucet, I notice that it works so beautifully and smartly also. It's also easy for anyone who loves 'do-it-themselves' installation. its nice sleek style also well match with our modern bathroom design.


Cologne Germany is one of the biggest exhibition centres in the world. Their "messe" halls have excellent and clean public facilities. What they have are floor mounted, foot operated faucets and toilet flushing systems. Purely mechanical and damn clean I think.

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