But these days, with new concerns about water safety, dozens of brands of bottled water, and filters with names you'd need a Ph.D. to decipher, choosing your water can be something of a challenge. A few simple guidelines can help. Tapping a source Tap water can contain a number of chemicals, pesticides, parasites, and other contaminants. Unfortunately, there are many more of concern.
Chlorine is used to kill microbes in many treatment facilities.
But chlorine-resistant parasites, such as Cryptosporidium, are a particular hazard to the young, elderly, and sick. Murkiness that persists for more than a few minutes may be a sign of contamination, so boil your water for five minutes to kill these organisms. Chlorine itself has also raised concerns. The FDA says it's safe. But it can, for instance, react with leaves and organic debris in reservoir water to form cancer-causing compounds called trihalomethanes.