Today's question: How are germs kept out of my drinking water?

Plain Talk answer: At most water treatment plants, a chemical disinfectant is added that kills most living organisms in the water. Chlorine gas and its liquid (sodium hypochlorite) and solid (calcium hypochlorite) forms are the most common disinfectants used in the United States and Canada. The discovery of chlorine’s effectiveness at killing cholera and typhoid germs has been heralded as one of the most important health discoveries of the 20th century. Other disinfectants include chloramines (a combination of chlorine and ammonia), potassium permanganate, ozone and ultraviolet (UV) light. Your water supplier can tell you what disinfectant is used in your water.

Private water sources usually are not disinfected and should be tested annually to uncover possible contamination.

Some organisms, such as Cryptosporidium, are chlorine resistant, and water suppliers that use surface water use a multiple-barrier treatment process that includes filtration and, at times, ozone or UV to remove these organisms from your drinking water.

For more information on this and many other water-related topics, check out Plain Talk About Drinking Water by Dr. James M. Symons.