What is the appropriate time to boil water to ensure its safety for drinking?

Boiling water for 1 minute is widely considered to be the appropriate method to ensure its safety for drinking. This duration effectively kills most microorganisms, including bacteria, viruses, and protozoa, which might be present in the water. The World Health Organization and the Centers for Disease Control and Prevention recommend boiling water for at least 1 minute at sea level to achieve this level of safety.

At higher altitudes, where the boiling point of water is lower due to decreased atmospheric pressure, it is advised to boil water for a longer duration — usually up to 3 minutes — to ensure its safety. However, in general conditions, boiling for 1 minute is sufficient for disinfection, making this the correct choice.

The other durations mentioned, such as boiling for 1 second, 30 seconds, or 10 minutes, are either inadequate or excessive. A boil of only 1 second or 30 seconds may not reliably eliminate all pathogens, especially in cases of viral or protozoan contamination, leading to potential health risks. On the other hand, boiling for 10 minutes, while certainly safe, is unnecessary for achieving disinfection and represents an inefficient use of time and resources in most situations.