Every day, millions of people drink chlorinated tap water. Chlorine is used to keep our water clean by disinfecting it and killing germs. And it does a marvelous job at eliminating most pathogens from the water we drink. But the use of this powerful chemical has a downside. According to a report from the U.S. Council of Environmental Quality, the cancer risk for people who drink chlorinated water is up to 93% higher than for those whose water does not contain chlorine.