What is the recommended maximum level of chlorine residual in drinking water?

The recommended maximum level of chlorine residual in drinking water is often cited as 4.0 mg/L. This level is considered safe for maintaining the disinfection of drinking water while minimizing potential health risks. Chlorine is an effective disinfectant that helps in the reduction of pathogens in water supplies, but excessive levels can lead to unpleasant taste and odors, and may pose health concerns over long-term exposure.

Regulatory agencies, such as the U.S. Environmental Protection Agency (EPA), have established this upper limit to ensure that the water remains safe and palatable for consumption. It balances the need for effective disinfection with the need to minimize any potential adverse effects on public health. Chlorine levels above this recommended maximum can also promote the formation of disinfection byproducts, which may be harmful to health.

Understanding the appropriate chlorine residual levels is critical for water distribution professionals to ensure the safety and quality of drinking water delivered to consumers.