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How Long To Boil Drinking Water?

June 5, 2014, by Ken Jorgustin


The U.S. Environmental Protection Agency reports that 90 percent of the world’s water is contaminated in some way. There are a variety of microscopic organisms that can contaminate water supplies and cause potentially serious, even fatal, illnesses among wilderness travelers.

Dipping your head into a cold mountain stream and taking a long refreshing drink is an experience that has basically vanished from the wilderness and other areas of America.

How many minutes does it take to boil water until it’s safe to drink?

Biologically contaminated water is water that contains microorganisms such as “Giardia” (a common microorganism that, if not killed, leads to intestinal disorders), bacteria, or viruses that can lead to infections.

Ever heard of traveler’s diarrhea? Ever been afflicted while on a hiking or camping trip as a result of drinking water that you thought was perfectly safe? One word… “Giardia”.

Toxic water sources however contain chemical contamination from sources like pesticide runoffs, direct dumping or indirect leaching, mine tailings, and so on.

Boiling, filtering, or chemically treating water can remove or kill microorganisms,
but it will not remove chemical toxins.


Time To Boil Drinking Water

Boiling is the most certain way of killing all microorganisms.

According to the Wilderness Medical Society…

Water temperatures at 160° F (70° C) kill all pathogens within 30 minutes.
Water temperatures above 185° F (85° C) kill all pathogens within a few minutes.

So in the time it takes for water to reach the boiling point (212° F or 100° C) all pathogens will be killed, even at high altitude. The moment your drinking water reaches a rolling boil, the water has already become safe to drink.

Backpacker thermometer purposed towards safe drinking water:

Used for monitoring temperature in food service applications, and its stainless-steel probe has a thermistor sensor in the tip for taking measurements while immersed in liquid or air.

Cooper-Atkins Digital Pocket Test Thermometer, Waterproof

NOTE: Caveats regarding Safe Water Boil Times:

Boiling water will NOT remove chemical toxins that may be present.

Very dirty water should be filtered first with a cloth or other material to remove sediments, and/or let stand for awhile to allow sediments to settle – then pour off clearer water on top.

Stop wasting fuel. You do not need to boil water for 5 minutes, 10 minutes, double for high altitude, whatever else you’ve heard, etc.

If you have a thermometer, you don’t even have to wait until the water begins to boil for safe drinking water…


How Many Minutes To Boil Water Until Safe To Drink

30 minutes at 160° F

3 minutes at 185° F

Instant at 212° F