I'm going on a one day hike, and I want to cook an egg whilst on it. I'd like to avoid carrying excess water, and the route goes past a couple of waterfalls and several streams, so there is no problem in acquiring extra water. However, I don't know whether there would be risks from bacteria in the water getting into the egg, meaning I would have to purify the water first.

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    Chicken eggs shells are porous - this site which is to do with general egg production has some interesting information about washing eggs / bacteria poultryclub.org - I've never personally cooked an egg in dirty water, but do keep chickens and we always wash our eggs after they have been laid but that's it.
    – Aravona
    Sep 3, 2014 at 10:07
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    Can you clarify do you mean dirty water or simply water that hasn't come out of a tap?
    – user2766
    Sep 3, 2014 at 10:21
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    @Liam Either - I imagine that the water will be physically clean, but I'm not sure.
    – rlms
    Sep 3, 2014 at 10:33
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    @Aravona Interesting side-fact: In the USA, law requires that eggs are washed before they can be sold. They thus always require refrigeration. In the EU however, you are not allowed to wash them. This keeps the natural protective film intact which simply dries. Unwashed eggs don't need to be refrigerated for a couple of weeks. If you get eggs in the US, I'd thus hard-boil all the eggs before starting the trip. That way, they are also safe for a couple of days probably. Sep 3, 2014 at 16:05
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    According to this boiling for 1 minute should be enough to deal with Giardia, boiling an egg will take longer. +1 on boiling the eggs before you leave, it's easier anyway :)
    – AVee
    Sep 3, 2014 at 16:10

3 Answers 3


First things first. You do not need to purify all water sources. Just because it is not out of a tap does not make it immediately dirty. Most fresh wilderness water (providing it isn't stagnant, etc.) is fine for drinking.

You should be familiar with the source of the water. Just because the river looks clean doesn't mean that an industrial unit isn't dumping into it upstream. I always check a river on a map before using it. Generally a mountain stream above human habitation will be fine.

Providing the water is fine for drinking there is no reason not to boil an egg in the same water, if anything it's going to be safer.

If the water is actually dirty (e.g. polluted, stagnant, in a built up area, etc.) Then no, don't boil your egg in it.

Most bacteria should be destroyed by the boiling, but things like heavy metals, etc. will survive boiling and this can either enter the egg (though the shell) or be passed onto the inner egg from the shell when you break it (cross contamination)

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    Liam -- regarding the first part, based on what I've read in the past, shouldn't one be wary of all wilderness water (even fast-moving) because of the potential for things like tapeworm eggs from animal droppings?
    – Daniel
    Sep 3, 2014 at 18:04
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    Most "fresh wilderness water" is far more "fine for drinking" than the processed concotion for which you pay $x per bottle at home. Nature is better at this than we are. Sep 4, 2014 at 0:27
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    @Doc: based on what I've read in the past, shouldn't one be wary of all wilderness water (even fast-moving) because of the potential for things like tapeworm eggs from animal droppings? Where have you read this, and what wilderness areas do you have in mind? There is copious evidence that, e.g., water in the Sierra does not need to be treated. Are you thinking of giardia or other protozoan cysts, and perhaps misremembering this as tapeworms? In any case, there is no known disease-causing organism present in backcountry water that would survive boiling.
    – user2169
    Sep 4, 2014 at 3:12
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    @Doc In my experience this risk is significantly overplayed. The geographic location needs to be taken into mind but providing it's a fresh, fast flowing mountain stream over stoney ground there is very limited chance of disease. Your biggest issue is human pollution. Almost all bacteria and parasites cannot live for long periods in fresh water and any that do will be so diluted your chances of contracting one would be minuscule. Many, many people (including long treks where carrying water isn't practical) rely on none tap water.
    – user2766
    Sep 4, 2014 at 10:36
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    Now now people. Arguments should be conducted in the chat room
    – user2766
    Sep 4, 2014 at 13:11

As someone with +10 years experience as a boy scout, I have never had an incident or heard of an incident where cooking with wilderness water led to bacteria infections, sickness, etc.

You should take care not to use stagnant water (this was also mentioned in other answers) and I'd personally avoid very shallow streams, to avoid dirt and bacteria from the ground polluting the water.

If you want to be as safe as possible, make sure the water has been boiling for some time before putting the eggs in it.

On a sidenote:

Since it is supposed to be a one-day hike and you don't mention anything else, I assume that the trip will be somewhere near to you. If you are visiting a foreign country, I'd definitely make sure beforehand that the water sources there are safe to drink from (i. e. I probably wouldn't do this without proper water filtration in some African or South-American (or even European) countries).


Yes you can but the question you need to ask yourself is should you ? If the water is dirty it will contaminate the egg (some toxins are horribly bad for you)

Most fresh (flowing) spring water is VERY clean if above human habitation areas


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