Questions and Answers About Your Water

If I had no chemicals, no fire, and no filters, is there any way I could make stream or lake water safe to drink?

The World Health Organization (WHO) offers a suggestion. If you are in a warm climate, have plenty of sunshine, a black surface, and a clear plastic soft-drink bottle, fill the bottle about half full and lay it on its side on a black surface in the bright sunshine for about five hours. According to WHO, this will kill most, but not all, germs in clear water. The hotter the air temperature, the better. Although not perfect, this method, called "solar water disinfection," would be better than drinking untreated water. 

Excerpted from Plain Talk About Drinking Water by Dr. James M. Symons. For answers to more of your drinking water questions, buy the book at the AWWA Bookstore .