How long must you boil water to purify it?

To effectively purify water through boiling, it is widely recommended that water be boiled for at least 1 minute to ensure that most pathogens, including bacteria, viruses, and parasites, are killed. This boiling time increases to 3 minutes at higher altitudes (above 6,500 feet) because water boils at a lower temperature at those elevations. Boiling water for 15 seconds may not be sufficient to eliminate all harmful microorganisms, making that duration inadequate for proper water purification.

Therefore, the most effective and widely accepted practice is to boil water for at least 1 minute to ensure its safety for consumption. While some might reference shorter durations under specific conditions or for certain pathogens, the 1-minute guideline is a general safety standard.