Water is sterilized by bringing it to a rolling boil for one minute. At elevations over 6,500 feet, the water must boil for three minutes.
If the water is cloudy, it must first be filtered through a clean cloth, coffee filter or paper towel, or it can be allowed to settle before boiling. After drawing off the clear water and boiling it for the prescribed time, the water must cool before being stored in containers that are clean and sanitized and that have tight-fitting covers.
Boiling water is the best way to ensure that water is safe to drink, especially if its quality is questionable following an earthquake, flood or other incident. Boiling kills bacteria, viruses, parasites and other disease-causing organisms.