I ask this question since I spent a week in a science lab recently with a stream of eager 7-11 year olds coming in to learn how to be water smart. This was part of Thames Water’s fabulous Water Efficiency in Schools Programme, and one of the main messages we give out is the importance of short showers, always culminating with us setting them the four minutes shower challenge (though us being us and very keen not to make anyone feel left out we always set a four minute bath challenge to the kids who don’t have showers.) Our usual modus operandi when we are in schools is to  career madly round the school from one classroom to the next with a pile of scratchily completed feedback forms, an inflatable flamingo, a see-through toilet cistern (now with see-through WC siphon to boot – big thanks to Josh at Thomas Dudley for that), a 5 litre ex-bottle of water, a memory stick (if we’ve remembered to remove it from the computer) my reading glasses (in my dreams), badges (green I’m a water detective, blue I’m water aware – aka the “when are we getting our blue badge?” badge) whilst trailing four minute shower timers in our wake. And that’s us on a good, everything under control, day!


So, being stationed in the same room, teaching them water as part of their science week, gave me so much thinking time it unlocked something in my brain and I began to talk about social scientists carrying out a series of experiments to see exactly how long it took to get clean as it wouldn’t be sensible to set a four minute shower challenge if it actually took longer than that. Which then got extended into that after four minutes the rest of the time they are in the shower is spent marvelling how it is the best invention EVER and wondering whether the person who invented showers won the Nobel Prize cos they really should have done…


It worked a treat until the weekend when I wondered whether that scientific research really had been carried out or whether I too had entered the post-truth world. So back in the office and a chance to google for the definitive research…Of course that wasn’t as easy as I had hoped due to Google thinking it knows what everyone wants. Which in my case was to keep on telling me about the four minute shower challenge even though I had not actually put the word ‘four’, nor the word ‘challenge’ in there!  Luckily I remembered I knew some academics, so fired out this question:

Any chance you know of any research done on how long it actually takes to get clean in a shower? Surely there must be some obscure 1960’s American research where human guinea pigs were measured for dirt before and after xx minutes in the shower. And xx was four. Here’s hoping!


Bish bosh, back flooded the replies…. And what they all said was …check out Alexander Kira.

‘My first port of call would be Alexander Kira’s book on the ergonomics of the bathroom. If you’ve not got it, get someone to get it for you for Christmas. It’s wonderful!’ (Judith) ‘Alexander Kira did all sorts of ‘ergonomic’ experiments with people and bathroom designs (exactly the 1960s human guinea pig research with sci-fi photos you were hoping for).’(Sarah) ‘Kira has a chapter devoted to showers but it focuses on optimising design criteria, not on optimising bodily cleansing – though he studies typical usage in great depth.’ (Barbara)


So I did! And here’s what I found out. Firstly, Sarah was not wrong about the photos being weirdly sci-fi – I would probably add dystopian to the description, as in: A dystopian future world where you shower in front of graphs and measuring lines whilst reels of black and white negatives are taken to ensure you are not in the shower for too long – hey hang on a minute… maybe I’d quite like that? Only kidding dear reader….


Secondly Kira was a US scientist in the 1960’s who looked at how people used stuff in the bathroom.  He wrote a whole book about it called The Bathroom (first published in 1966, revised in 1976, no longer in publication but you can get a second hand copy of it in www.land so I am on it car bonnet). Basically he thought everything in the bathroom, not just showers needed to be radically redesigned. These are his observations on how badly showers were designed: ‘Of all the normal body cleansing activities these (the cleaning of genital, anal and urinary bits) are undoubtedly the least understood the least discussed, and the least performed.’ And, One can get a car washed automatically in five minutes, while it still takes us 15 minutes to wash ourselves by hand.’


It’s a great quote, but somewhat scuppers my ‘scientists say it takes four minutes to get clean’ claim… So, I am still searching… because wouldn’t it be great if the four minute shower challenge was actually based on scientific research? As opposed to: ‘My guess is the 4 minute timer was probably invented by a water efficiency team somewhere as the lowest possible shower length that they though people will abide, rather than a scientific study of cleanliness’ (Sarah – an academic) or ‘I think it was based on the perceived urban myth at the time that the average shower was five minutes so just knock off a minute and we can just use four minute egg timers cos plenty of those already being marketed so a bit of rebranding and bish bosh sorted’ (Cath – plumber/suit).

December 2016 – how long does it actually take to get clean in the shower?