Bringing water to a boil kills any organisms in it. Contrary to the advice given in many other sources, the water does not have to be boiled for “ten minutes plus a minute for every thousand feet above sea level” or for any of the other recommendations you may have read about! The time it takes to bring water to a boil and the temperature of the water when it boils is sufficient to kill Giardia, Cryptosporidium and any other water borne pathogens. Recognizing that the boiling point of water decreases as you climb higher the temperature at which the water boils is still hot enough to kill those organisms that might make you sick. Continuing to boil the water wastes fuel, evaporates the water and delays consumption. Overseas, especially in developing countries where river systems are still a frequent method of sewage disposal, boiling for a longer period of time (one or two minutes) is advisable. Keep in mind that being able to boil water to disinfect it is dependent on having fuel available to burn; a metal container to heat the water in and the time it takes to boil the water.