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Is it okay to wash your hands in the same dishwater that you are using to wash the dishes? In other words, Can someone use the kitchen sink filled with soapy dishwater to wash hands after using the restroom? Is it safe or just gross?

FuzzyChef
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tcutts
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    This was actually the punch line of a professional comedian here ("I always wash dishes after I poop, very efficient, washes my hands at the same time", delivered in a deadpan voice) and the audience collectively went "Eeewww!" – Peter - Reinstate Monica Dec 02 '21 at 16:11

2 Answers2

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No! This risks fecal contamination of the dishes.

One of the most common methods for disease to spread is the fecal-oral route. By washing your hands after going to the toilet in the same water as the dishes you're cleaning, you're transferring that fecal contamination to the water and then to all the dishes washed in it, and then to all the food eaten from those dishes.

nick012000
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    Your answer reminds me of a person who was repulsed by the thought of washing their underwear with their other clothes. Do you also wash dishes that held raw food separate from cooked food? I say that washed hands in the same dish water makes no difference and your link is not quite the same thing. – Rob Dec 01 '21 at 11:14
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    @Rob "Do you also wash dishes that held raw food separate from cooked food?" That shouldn't matter. The water should be hot enough to kill any bacteria from that - but if it's cold enough to wash your hands in, it's too cold to do that. – nick012000 Dec 01 '21 at 13:46
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    @Rob There are likely two scenarios at play here— a home cook, and a professional. For a professional, this would be a health code violation. For a home chef, maybe you won’t get hundreds of people sick, but you’ve just walked all the way from the bathroom to the kitchen without washing your hands. Did you touch and doorknobs or light switches on the way back to the kitchen? I admit I’ve washed my larger pots in the bathtub before, but that was because I lived in an apartment with a tiny sink that couldn’t even fit my plates unless they were at an angle. (The kitchen was about 5ft wide) – Joe Dec 01 '21 at 14:43
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    @Rob re washing dishes: If you wash glasses, then table crockery/cutlery, then prep stuff and cooking pots, you're very nearly washing the raw stuff separately – Chris H Dec 01 '21 at 15:04
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    @nick012000 washing up water is rarely hot enough to kill stuff, which would require over 60°C for some time. It probably doesn't come out of the tap at 60°C and you wouldn't want to repeatedly reach into a bowl of 60°C water for things anyway – Chris H Dec 01 '21 at 15:05
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    @Joe as a temporary setup I've done something similar (though a bowl on a board over the bath is far more ergonomic). When it comes to cramped, in my campervan there's only one sink and (cold only) tap - so before using the toilet I have to make sure the sink is clear for handwashing (there's also very limited space, so the sink is rarely clear) – Chris H Dec 01 '21 at 15:12
  • @ChrisH And no one does that order of washing dishes. And no one washes dishes separately if they noticed flies landing on a plate. In most normal living environments, living things get along, and despite sounding disgusting, no harm will likely occur. – Rob Dec 01 '21 at 16:00
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    "you wouldn't want to repeatedly reach into a bowl of 60°C water for things anyway" That's what the rubber gloves are for. If the water's not hot enough to feel like it'll burn your hands if you're not wearing gloves, it's not hot enough. – nick012000 Dec 01 '21 at 16:10
  • @Rob that's a very sensible order, but not mainly for hygiene. It's efficient to go from things that show grease marks but aren't very dirty (glasses) to things that leave the water greasy (frying pans) – Chris H Dec 01 '21 at 16:23
  • @Nick maybe, I don't wear them. But then the little hand-washing I do is baking stuff and similar. Everything else goes in the dishwasher (at 50°C but of course that's chemically harsh) including anything from the very rare occasions I cook meat. But the gloves won't keep your hands happy in 60°C water for long, and by the time you've warmed a few plates in it, even if it was 60° when it came out of the tap (that's a likely upper limit), it's not for long. And even 60° isn't enough to kill everything nasty in the minute or so a dish is in the water. – Chris H Dec 01 '21 at 16:27
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    it may be worth stating explicitly that this criticism applies only to washing hands after using the loo, and not after food prep – Tristan Dec 02 '21 at 10:55
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    @nick012000 Most tap water doesn't go above 60C (140F), and you'd need to hold your hands in that water for 12 minutes to be good bacteria-wise according to food-safety time-temperature tables (see http://www.foodprotect.org/issues/packets/2012packet/attachments/iii_018__all.pdf), at which point you'd have 3rd degree burns from the water (5 seconds @ 60C is enough for a 3rd degree burn: https://ameriburn.org/wp-content/uploads/2017/04/scaldinjuryeducatorsguide.pdf). – bob Dec 02 '21 at 13:48
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    @Tristan unless you've been handling some very organic produce. Seriously though, after harvesting muddy stuff from my garden I wouldn't wash my hands in the washing up water – Chris H Dec 02 '21 at 17:30
  • that's also a good point! There definitely is some food prep after which that could be significant – Tristan Dec 02 '21 at 17:40
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    @Bob - there's a cutoff on my water-heating system that kicks in at 56C and I believe my system is common enough (when my wife complained to our plumber that the water wasn't hot enough for her, he explained the 56C cutoff and showed us where it cutoff was and how to dial it up to around 60C. It would apparently go a little higher [I think he said 66C] but he would not recommend it, even in a house with no kids, due to the risk of scalds from water straight out of the tap). – Spratty Dec 03 '21 at 10:29
  • @Spratty mine is set to a similar temperature, but note that going much lower is a bad idea because legionella can survive up to about 60°C (and grow up to about 45°C) while high 50s is still enough to scald – Chris H Dec 03 '21 at 16:43
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I completely agree that after the toilet it's a very bad idea. Just don't. Food hygiene regulations for commercial settings, strictly interpreted, are likely to mean that you wash your hands after the toilet and on arrival in the kitchen, i.e. again.

If what you're washing off is from food prep, it's less clear-cut. I still wouldn't recommend it in a professional setting, where there should always be a separate hand-wash sink. At home, when cleaning as you go, sometimes you have little choice. I find this especially true when batch-baking, or when preparing a lot of fruit/veg for several dishes at once - you may need to wash the onion smell off before prepping dessert, for example. Then you're either washing in or over the washing up water.

Somewhere in between is dirty food-prep. By this I mean tasks like getting soil off root veg transfer the soil to your hands. You wouldn't want that in your washing-up water either. Of course that's fairly unlikely as you'll need a sink to clean the veg, so you'll have somewhere to wash (once the veg is out of the way so you don't get soap on it).

Chris H
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