What is the maximum recommended chlorine residual for public water systems?

The recommended maximum chlorine residual for public water systems is established to ensure safety and effectiveness in water treatment while minimizing the potential for adverse health effects. A chlorine residual of 4.0 mg/l strikes a balance between adequately disinfecting the water to prevent harmful microorganisms and limiting the formation of chlorination byproducts that can be harmful at higher concentrations.

Chlorine is widely used in water treatment as a disinfectant, but higher residual levels can lead to taste and odor problems, as well as potential health risks associated with exposure to disinfection byproducts. Public health guidelines typically emphasize maintaining a residual level that ensures water safety but does not exceed recommended limits. Hence, a maximum of 4.0 mg/l is considered appropriate for public water systems to effectively manage these concerns while ensuring public health safety.

Other values may exceed this recommended limit, which could lead to increased health risks or consumer dissatisfaction due to taste and odor issues in treated water.