What minimum level of free chlorine is mandated by the National Interim Primary Drinking Water Regulations?

The minimum level of free chlorine mandated by the National Interim Primary Drinking Water Regulations is 0.2 ppm. This regulation is established to ensure that there is sufficient disinfection in public water systems to eliminate harmful pathogens and provide safe drinking water for the population. Free chlorine serves as an effective disinfectant, and maintaining it at this minimum level helps protect public health by reducing the risk of waterborne diseases.

Other concentration levels, such as 0.05 ppm, 0.1 ppm, and 0.5 ppm, do not meet the regulatory requirements set forth by the National Interim Primary Drinking Water Regulations. They might either fall short of the necessary disinfection level or exceed recommended limits, which could lead to taste and odor issues or other undesirable effects.