What is the target range for chlorine residuals in water distribution systems?

The target range for chlorine residuals in water distribution systems is indeed 0.2 to 4 mg/L. Maintaining chlorine residuals within this range is essential for effective disinfection and ensuring that harmful pathogens are controlled throughout the distribution system. Chlorine is commonly used because it is effective in killing a wide variety of microorganisms and helping to maintain a level of disinfection throughout the system.

The lower limit of 0.2 mg/L is necessary to ensure that there is enough disinfectant present to inhibit bacterial regrowth, while the upper limit of 4 mg/L prevents potential taste and odor issues as well as minimizing the formation of disinfection byproducts that can occur at higher concentrations.

In practical applications, operators must frequently monitor chlorine levels to ensure they remain within this designated range, adjusting feeding rates as needed to maintain water quality and safety for consumers. This balance is crucial for public health while also considering the aesthetic aspects of the drinking water.