Benefits of Water Chlorination
 TWUA Newsletter March 8 2022

When we think of chlorinated water, usually a swimming pool is what comes to mind. But did you know that water plants nationwide utilize chlorine as a disinfectant to prevent water-borne illnesses and disease? 

Chlorine effectively kills a large variety of water-borne pathogens, including those linked to dysentery, cholera, and typhoid fever. In fact typhoid fever has essentially been eliminated thanks to water chlorination. In the 1990s, Life magazine was once quoted as saying, “the filtration of drinking water and use of chlorine is probably the most significant public advance of the millennium.”

Microorganisms are found in raw water sources, like from rivers and lakes. Although not all microorganisms are harmful to our health, some (called pathogens) can cause diseases and other illnesses in humans.

Along with water treatment processes (like sedimentation and filtration), chlorination allows water to be safe for public consumption. Water chlorination is now used in over 98% of United States water treatment plants. 

Back in the 1800s, chlorine was first used in water to remove odors from the water that were thought to be causing illness outbreaks. It wasn’t until almost a century later that chlorine was found to be a disinfectant tool, reducing disease transmission via drinking water. 

Not only is chlorination used to eliminate harmful microorganisms, but also to reduce the chance of pathogen growth in storage tanks or water distribution systems, where water can often sit until needed. Now that the use of chlorine for drinking water is widely used, government bodies have set guidelines for the amount of residual chlorine that must be present at all points of a water system, while also keeping it at safe levels for human consumption.

So chlorine kills pathogens and other microorganisms that are harmful for human health. How is chlorine safe for us to ingest? According to Scientific American’s article on water chlorination, “when we ingest chlorinated drinking water, food in our stomachs and the materials normally present in the intestinal tract quickly neutralize the chlorine.” Sure, at much higher concentrations chlorine could damage the cells in our body. 

In 1974, the United States Congress enacted the Safe Drinking Water act, and was later amended in 1986, expanding the Environmental Protection Agency’s role in regulating safe drinking water. This act requires the EPA to control specific disease-causing organisms and other pathogens, while also requiring public water supplies to properly disinfect water. 

Chlorination is not the only disinfection agent available for water utilities, but it remains the most widely used. As new technologies for water disinfection emerge, we must remember all that chlorinated water has done for public health since it was first utilized.