Also, just making the toothbrush wet fools nobody

A reader writes:

I wash my hands after going to the bathroom. I do, honest! But... maybe if I've only had a wee, I might just sort of... splash them a bit.

I know I'm being disgusting. How disgusting am I being?


Washing your hands without soap has almost no impact on the amount of bacteria on your skin. The only reason to do it is if all you want to clean off your hands is something, like, I don't know, sand or poster paint or something, that plain water easily removes.

But if your hands are covered with, for instance, garden soil, you may be able to get them apparently clean with plain water, but plenty of bacteria from the soil will still be there.

(UPDATE: It seems that it's a bit more complicated than that. Some researchers have found that you actually can wash your hands effectively without soap! You need to rub your hands together "purposefully" for at least 20 seconds under running water, though.)

Holding, not to put too fine a point on it, your penis while you urinate, probably will make your hand (or hands; I'm making no assumptions about your technique or dimensions) significantly more bacteria-laden. And the bacteria you pick up there can be nasty ones. Coliform bacteria, including ones that can cause an unpleasant stomach upset at the very least, are all over normal human skin in the approximate area that boxer shorts cover. You can't get rid of the buggers completely without bathing in antiseptic and scrubbing yourself with a wire brush.

(This is why no amount of bathing will prevent your armpits getting smelly when you start sweating again. The smell is the metabolic products of bacteria that thrive in sweat, and those bacteria live in the pores of your skin and can't all be killed without killing, or physically removing, the skin as well.)

Washing your hands with ordinary soap does, fortunately, get rid of coliforms on the surface of the skin, which is where they'll be if you've just been handing your privates. The soap doesn't kill the bacteria, but it gets rid of the oil on the surface of the skin, and washes most of the surface bacteria away with it.

(Hand sanitiser is usually based on alcohol, which also cuts the oil on your skin and actually does kill bacteria quite effectively. Washing with soap gives you live bacteria going down the plughole; hand sanitiser without washing gives you dead bacteria still sitting on your skin.)

And yet, persons in a normal state of health who don't wash their hands at all after going to the toilet will, demonstrably, not cause themselves, and everyone else they touch, to constantly get gastroenteritis. This is because bacterial transfer and growth is a statistical sort of thing.

Harmful strains of bacteria, and viruses for that matter, only become a problem when they get into your body, and can multiply faster than your immune system can get rid of them.

Let's say you've got a normal immune system, and you go to the bathroom, wash your hands in a perfunctory manner with no soap, and later on decide to eat some chips or perform some other activity that transfers bacteria from your hands to the upper portion of your gut.

You'll probably be fine, just as you will probably also get away with driving while mildly-illegally drunk.

But doing this buys you quite a lot of tickets in the Pathogen-Disaster Lottery. If you get a big enough dose of bad enough germs into yourself, your immune system won't be able to react and shut them down before they've multiplied into too large a population to stop, and then you'll be in trouble.

Which, again to not be over-dramatic, probably won't be the kind of trouble that kills you. But may be the kind that initially makes you afraid that you will die, and later on makes you afraid that you won't.

(Going around covered with nasty microorganisms also makes you a significant hazard for people with lousy immune systems - the very young, the very old, and the otherwise infirm. You don't even need to touch them; every time you leave a germy handprint on some non-antimicrobial surface, it'll wait there for quite some time to give the microscopic gift that keeps on giving to someone else.)

Any kind of hand-washing with soap will reduce the number of tickets you buy in the lottery you don't want to win, and washing your hands thoroughly with soap makes the risk essentially zero. (To do it properly you're meant to take at least 20 seconds, which can seem a rather long time while you're staring at yourself in the bathroom mirror.)

It's not just bacteria from your own body you have to worry about, of course. There are also pets, and rubbish bins, and all of those surfaces you have to touch any time you leave the house, and other people, and of course also other people's sticky, shrieking, waste-encrusted offspring.

My partner, a while ago, got really horrible gastroenteritis, the kind that sees you in hospital being intravenously hydrated on more than one occasion. I managed to get through the experience without getting the bug myself, and I didn't wall myself up in the attic and only touch her with robotic waldoes to achieve this. You'd better believe I washed my hands often, though.

Ever since, I wash my hands properly whenever I come home, and whenever I've handled anything that could plausibly be well-loaded with bacteria and/or viruses. And I've not had any tummy bugs since - though I didn't get them frequently enough beforehand for this to have generated any statistically significant data.

You don't need to go completely Howard Hughes about all this, but you also don't need to work in a hospital for a greater than zero level of germ-consciousness to be worthwhile.

Note that unless you've got a bladder infection or something, urine itself is very close to sterile (not quite fully sterile, because even a healthy urethra can contribute a few bacteria to it). Nice and warm, too.

So if you just put a soap dish on top of the toilet, you could probably get the whole job done in one operation.

(The non-comedy version of this is the cistern-top sink, available in relatively modest and also huge expensive designer versions.)

Psycho Science is a regular feature here. Ask me your science questions, and I'll answer them. Probably.

And then commenters will, I hope, correct at least the most obvious flaws in my answer.

20 Responses to “Also, just making the toothbrush wet fools nobody”

  1. Mohonri Says:

    I saw one of those sink-toilet combinations on a business trip to Japan a couple years back. I thought it a fantastically simple way to reduce water usage (and save space in tightly-packed Tokyo at the same time!). The water you use while washing your hands drains into the toilet tank, and the toilet fills at precisely the same time as you wash your hands anyway.

  2. ix Says:

    Brings me to my favourite word: fomite.

    I'd also like to point out killing the microbes on your hands (at least, the alcohol-based ones) is not necessarily a good thing. Not only do a lot of the microbes on there perform important functions such as maintaining skin Ph (killing invaders), they also prevent other more nasty organisms from colonizing your hands.

    Probably you're okay when using the antimicrobial products; I can't imagine they actually work very well. But stay away from alcohol-based products unless you work in a hospital or prepare food with your bare hands.

  3. RichVR Says:

    As a New Yorker I have a healthy fear of picking up something nasty on my hands. You see, I ride the subway. If you shuddered at that, welcome to the real world. From the moment that I touch anything in or leading to the train, I make it a habit to remember to keep my hands away from my face. I can't count the number of times that I have seen some disgusting bastard (or bastardette) sneeze into their hand and then grasp a pole or handrail.

    It makes me want to puke just thinking about it. But of course that is nothing compared to grasping a pole yourself and encountering... STICKINESS...

    Of course this reminds me of the old joke. Two guys in a bathroom. One urinates and goes to leave. The other says, "Where I come from we wash our hands after we pee."

    The other says, "Where I come from we don't pee on our hands."

  4. strangefeatures Says:

    Another toilet hygiene tip: you should put the lid down to flush (particular if there are solids involved), otherwise the flushing action disperses microbes all over your bathroom, where they can settle on all kinds of surfaces. Such as your toothbrush. This tip comes courtesy of the bacteria expert whose name I forget, but who was also the guy who noticed that sponges are more microbe-infested than toilet seats, and who named his daughter 'Escherichia'.

  5. RichVR Says:

    And don't forget one of the most evil devices in the home. The TV remote.

  6. RyanJ Says:

    ** Public Service Announcement **

    I was in the Men's room at work at the same time as a co-worker. He urinated and walked out without even the pretence of rinsing his hands.

    If any of you reading do this: you're a fucking disgusting grot - wash your filthy dick-smeared hands from now on, yeah?

    That is all.

  7. Max Says:

    I shudder to think what the upstanding fine gentlemen above might think of other er.... not-so-up-or-otherwise-standing er... gentle... people who occasionally consider entirely shunting the "hands" part out of said genitalia-hands-mouth path (for fun and profit, but mostly just for fun).

    Which is not to say of course all mentioned body parts shouldn't be washed anyway - just trying to put things into perspective; most of those people seem to do just fine, with surprisingly few cases of regretting-not-being-dead as far as I'm aware (although admittedly my actual statistical sample size is rather low). Clean is definitely good (and appropriate in these specific circumstances) but some people don't seem to have a realistic perspective on the likely consequences of occasional neglect. Unfortunately I can't remember whether the distinguished Penn & Teller got around yet to call bullshit on the "five-second rule" et al. but if they didn't, they should have.

    Here's a fun poll - how many public restrooms (in bars/restaurants/cinemas/fuel stations etc.) have you seen where the soap dispenser is still performing it's role (seeing as how water alone doesn't seem to do jack)? In my experience, about 60-70% at best, and I'm talking global here, not about the visibly seedy ones. Perhaps we should all be carrying hand sanitizers at all times for just such cases. Maybe an autoclave too, just to be safe...?

  8. jaypeabey Says:

    Dan, some of us enjoy oral sex and I haven't noticed any significant increased incidence of illness in my household compared to, say, other people my workplace. If anything, I'd take an slightly below average number of sick days.

    • cthulhubert Says:

      I hope you don't take this the wrong way, but I think there are some problems with your study. It's definitely statistically underpowered (given the sample group of 1). It also doesn't sound particularly rigorous (no control group, no bacteria counts, few controls on other variables).

      That is to say, you, personally, might just have a stronger immune system than the average person, and the occasional healthy-person's-junk to your-mouth contact isn't going to introduce enough bacteria to get a foothold. As Dan says, it's a statistical matter. Like driving drunk is bad because it makes death more likely, not because it kills someone 90% of the time it's done.

      I hope you'll forgive me if I don't leave to actually look for studies about increased risk for diseases based on incidence of oral sex.

      For one thing, it doesn't matter much. I don't want anybody to stop having sex because human fluid exchange is riddled with varieties of risks. Sure, precautions, like a shower first.

      Just don't, you know, give someone a handie and/or finger someone and then go high five all your buddies. Your immune system might be extra robust. Theirs? Their family's? The old woman on the bus that touches the "stop" button right after one of them? Maybe not. It's a matter of politeness more than anything else.

  9. Popup Says:

    As long as you're only exposed to a limited set of germ strains, you probably develop some kind of immunity. Just don't go around giving blowjobs to the entire office...

    • Anne Says:

      This is a good point. In particular, the majority of germ strains you get from your own nether regions will be ones that already inhabit your GI tract, so while eating them isn't exactly safe, it's not very likely to be harmful. Similarly for other people you are in regular contact with. I'd worry more about handholds on the metro, or, worse, anything in the hospital, than my own gut bacteria. That said, I like having clean hands, so I wash mine.

  10. rhy7s Says:

    "When hands were washed under running water with friction over a period of 20 s, the number of E. coli contaminating food and the skin surrogate was progressively reduced respectively to 0.18% and 0.34% of the baseline level. Running water alone was comparatively ineffective. The addition of soap showed a modest benefit. We conclude that in situations where hands are not visibly soiled, a purposeful hand wash under running water for 20 s, with friction, will deliver an effective outcome that can be improved marginally by the addition of soap."

    • rhy7s Says:

      Hey Dan, just wanting to check whether you'd want to modify the phrase "Washing your hands without soap has almost no impact on the amount of bacteria on your skin." in respect to the above study.

      • dan Says:

        Interesting! It does indeed seem that soap is not necessary, provided you rub your hands on each other "purposefully" for a full 20 seconds, under running water.

        I don't know whether these results have been replicated, but the protocol and tests are simple enough that I've no reason to believe it's wrong.

        The same researchers previously found that thorough drying of your hands after washing was important, for the washing to have a long-term benefit.

        So there are a surprising number of variables, here.

        I think it's still fair to say that using soap is the preferable technique, because it doesn't require you to keep your hands under running water for the whole 20 seconds - you can use a trickle of water to wet your hands and get them soapy, and then do the rubbing out of the water, then rinse off again; if nothing else, this could save a significant amount of water.

        And if you don't thoroughly dry your hands - which I think most people don't - then it's possible that antibacterial soap could be valuable, if it leaves antiseptic on the skin along with the left-over water.

        (For household purposes, antibacterial soap has been shown to be no better than regular soap at best, and it may actually be worse than useless.)

        The sort of perfunctory soapless washing that a lot of people do, lasting only a few seconds and without "purposeful" rubbing, still will achieve little.

        But yes, it seems that you can indeed wash your hands well enough for everyday purposes without any soap at all!

        • hagmanti Says:

          Actually, the link you provide (which misspelled Dr. Miller's name twice, so grain of salt as necessary) says "the crucial variable in a good hand wash is the friction generated by rubbing your hands together."

          I wouldn't be at all surprised if a dribble of water, followed by vigorous scrubbing, followed by a good rinse, was as effective or even more as rubbing them under running water...

          And, when it comes to antibacterial soap, Dr. Miller says "The average hand wash is 20 seconds. There’s no way an antibacterial can act in that time."

          And the Mayo Clinic would agree-- "Keep in mind that antibacterial soap is no more effective at killing germs than is regular soap." Plus, antibacterial soap leads to antibiotic resistance, and it does so in your immediate environs, which seems . . . short-sighted.

          Dan-- please think again on this-- recommending antibacterial soap is not up to your usual standards.


  11. kristina Says:

    What about women? We tend not to touch penises while we pee.

  12. cthulhubert Says:

    You better believe that I'm littering the Internet with links to this post Dan.

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