September marked a century of water chlorination in U.S. water supplies. Chlorine is used to disinfect drinking water and had contributed to reducing, and in some cases practically eliminating, water-borne diseases.
The first American drinking water supply to be disinfected with chlorine is in Jersey City, NJ. They’ve chlorinated drinking water since September 26, 1908. Today, most public water systems in the U.S. are chlorinated.
You can find more about the history of water chlorination here.
ACC Celebrates 100th Anniversary of Clean Drinking Water (American Chemistry Counci)
Marking a century of disinfection (American Water Works Association’s E-Mainstream)