365: Chemistry for Life
DAY 269

U.S. Drinking Water Chlorination: A Public Health Giant Step

Chlorine, a common component of drinking water and swimming pools, destroys germs and has helped to virtually eliminate waterborne illnesses like cholera and typhoid that once killed thousands of Americans each year.

Contributed by: American Chemistry Council, Chlorine Chemistry Division

Credit: iStock

The next time you enjoy a refreshing glass of water from the tap, consider a toast to chlorine chemistry, which has been helping to keep water safe and healthy for Americans for over a century. 

Exactly 103 years ago, on September 26, 1908, chlorinated water was first supplied on a permanent basis to a large U.S. municipality—Jersey City, New Jersey.  The results included a dramatic decline in the local typhoid fever rate and a water supply that, according to a 1928 sanitary engineering report, “is not only of a high sanitary quality, but…it compares favorably with the best in the country.”  

Chlorine destroys germs and has helped to virtually eliminate waterborne illnesses like cholera and typhoid that once killed thousands of Americans each year.  Near the close of the 20th century, Life magazine declared: “The filtration of drinking water plus the use of chlorine is probably the most significant public health advancement of the millennium.”  

Efforts to improve drinking water date to the time when ancient civilizations established themselves around water sources.  As early as 4,000 B.C., Sanskrit and Greek writings recommended filtering water through charcoal, exposing it to sunlight, boiling and straining it to reduce visible cloudiness. Other ancient civilizations such as Chinese, Arabian, Egyptian and Indian tried other coagulants, including almonds, powdered ginger, cornmeal, crushed oyster shells and even toasted biscuits.  These early attempts were based on the notion that clear water not only tasted and smelled better, but was not apt to make a person sick. What went unrecognized until the 19th century was that the cause of most waterborne illnesses was not visible and could not necessarily be removed by filtering.  Louis Pasteur and other scientists in the 1800s verified “germ theory,” which explained how organisms too small to be seen with the naked eye could transmit disease through water and other media. During the very late 19th and early 20th centuries, scientists turned their attention to removing “germs” in public water supplies using disinfectants like chlorine.  

Today, nearly nine out of 10 U.S. public water systems rely on chlorine to destroy disease-causing microorganisms.  But the story began 103 years ago on the west bank of the Hudson River in Jersey City when the power of chemistry over waterborne germs ignited a revolution that continues to yield public health benefits 100 years later.

Visit the official web site of the Chlorine Chemistry Division of the American Chemistry Council to read more about chlorine.

Excerpt provided by the Chlorine Chemistry Division of the American Chemistry Council.