Preparedness blog

Boiling Water in an Emergency Situation

By Jeff and Amy Davis
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hiking near contaminated waterWhether you’re backpacking the Appalachian Trail, camping with family or in a place where the water is un-sanitized, it is important to know how to make it safe to drink. There are various ways to purify water in the wilderness (filters and chemicals) but boiling water has been used by our ancestors for centuries. The first question you'll need to ask yourself when trying to stay hydrated in the wilderness is - where can I find water?

Water Sources in the Wilderness

Clear, flowing springs or streams away from people and manmade things is the most ideal place to find water. Lakes, ponds and rivers is the next best thing. Try to avoid stagnant water, there will be increased levels of bacteria, parasites and other contaminates. If you’re high in the mountains close to snow, this is another great alternative (as long as it is not black, yellow or brown). Always melt it down; this will prevent your bodies’ temperature from dropping. If you still can’t find water, start walking downhill and look for any vegetation.

How Long Should I Boil Water For?

A great rule of thumb to follow, regardless of where you find water is to boil it down. The Center for Disease Control (CDC) recommends that you boil water vigorously for 3 minutes if above 6,562 feet. Anything lower, boil it for 1 minute. 1 The Wilderness Medical Society also came out with a great recommendation that breaks it down even more.

160 ℉ - kill all pathogens in 30 minutes

185 ℉ - kill all pathogens in 3 minutes

In the time that it takes for water to reach the boiling point (212 ℉) all pathogens will be killed at any elevation level. The moment your water reaches a rolling boil, the water has already become safe to drink.

Very dirty water should be filtered with a cloth or material to remove extra sediments. You can also let the water settle and then pour off the clearer water on top.


5 years ago
Scot Frank
12 years ago at 11:58 AM
Can you please provides sources to qualify your recommendation that water is safe to drink as soon as it starts boiling? I have become sick many times after drinking water that just came to a boil.
Don Baird
7 years ago at 10:05 AM
How good or fresh is rain water, and should you always boil rain water? Thank you ~~~Don
jon donnelly
4 years ago at 4:20 AM
i read somewhere that on tops of high mountains that pesticides are killing plants because the rain brings it. i would boil it.... hope that helps
Harry Merkin
5 years ago at 1:03 PM
I use a Monolithic Filter. It's ceramic with charcoal. Filters out all the nasties, plus lead and other bad crap. Available for $40 online. If you are backpacking there are lifestraws and other items that will do the trick. ALWAYS CLEAN RAINWATER BEFORE DRINKING. Rain can run off a shingled roof into a barrel and bring petroleum products, bird poop, etc into your collection of water. Even a free standing barrel will have birds and small animals attracted to it which can leave droppings or dander or? Even if the critters don't get into it there are so many pollutants in the air that can get in there as the rain falls and collects it, that you really need to clean every bit of water you decide to consume where you don't know its origination point.
5 years ago at 2:10 PM
I have used several types of drinking straw filters. Some are very hard to draw water through. If you buy one try it out before you go out! I prefer a pump filter. There are also ultraviolet purifiers. Boiling is great but may not remove some 'flavors'.
Lisa Cate
5 years ago at 9:05 AM
Recommend a Kelly Kettle if you're going to be needing boiled water out in the woods. It uses a few dried sticks to boil water so it would save the cost of itself after a few times using it and also it's a more efficient way to boil water.
2 years ago at 10:11 PM
Boiling for any time longer than just starting a boil is a waste of fuel and time - both very precious in an emergency - nothing lives over 185degrees so cool the fire and save the fuel once the boil starts (or use it for something else).