What is the minimum chlorine residual requirement in water systems?

The minimum chlorine residual requirement in water systems is primarily established to ensure the effectiveness of disinfection processes and to provide a continuing protective barrier against pathogens. A chlorine residual of 50 mg/L is generally considered sufficient to maintain a residual disinfectant in the water distribution system. This level is adequate for preventing the regrowth of harmful microorganisms and ensuring water safety from the source to the consumer. Regulatory agencies set these standards to protect public health and ensure the microbiological quality of drinking water.

Higher levels of chlorine residual can potentially lead to taste and odor issues, as well as the formation of disinfection byproducts that might be harmful. Therefore, maintaining a balance is important, and the requirement of 50 mg/L reflects this careful consideration of both safety and aesthetic factors in drinking water.