Water disinfection in emergencies

In North America, we normally don't think twice about drinking the water coming out of our household faucets.  However, when there's a natural disaster (a flood, for example), that tap water may either be contaminated, or not flow at all.  If you don't have sufficient pure water on hand, you'll have to determine how to obtain clean drinking water.  When a widespread power failure combines with the natural disaster, domestic UV and reverse osmosis purification systems don't work, so alternatives have to be found.

If you have to deal with contaminated water, or water that you suspect is contaminated, there are three ways that FEMA, the Red Cross, and the EPA recommend:

  • Chlorination (16 drops / .125 teaspoons of unscented bleach per gallon)
  • Boiling (rolling boil for
  • Distillation

Particulate water filters are not recommended during an emergency because they only provide variable protection, and some can become a breeding ground for bacteria.