Why is water disinfection needed?

Disinfection of drinking water is one of the major public health advances in the twentieth century. In the early 1900s, typhoid and cholera were common throughout American cities; disinfection was a large factor in reducing these epidemics. Chlorine was the preferred disinfectant back then and continues to be the most widely used substance for water disinfection in the United States.

Public health officials overwhelmingly agree: In a 1992 survey of public health officials, 92% agreed that chlorine in drinking water is safe. Safe drinking water has played a key role in: a 50% plus increase in life expectancy, from about 45 years in the early 1900s to about 76 years at present; a dramatic decline in infant mortality rates and the virtual elimination of cholera, typhoid fever, dysentery and gastroenteritis, as well as many other waterborne diseases which once killed tens of thousands of Americans.