What is the maximum contaminant level (MCL) for residual chlorine in drinking water?

The maximum contaminant level (MCL) for residual chlorine in drinking water is set at 4 mg/L. This standard is established to ensure water quality and safety for consumers. Chlorine is commonly used as a disinfectant in water treatment processes to eliminate pathogens and maintain water quality during distribution. However, excessive levels of chlorine can lead to adverse health effects, and it's important that the MCL is adhered to in order to balance effective disinfection with the potential risks associated with higher chlorine concentrations.

Setting the MCL at 4 mg/L aligns with regulatory guidelines that strive to protect public health while ensuring that drinking water is adequately treated to remove harmful microorganisms. Chlorine's effectiveness as a disinfectant, coupled with the limits set by public health authorities, underscores the importance of careful monitoring of chlorine levels in drinking water systems.