What is the typical chlorine residual level maintained in water distribution systems?

Maintaining an appropriate chlorine residual level in water distribution systems is crucial for ensuring water quality and safety. The typical chlorine residual level found within established guidelines and practices falls within the range of 0.2 to 4.0 mg/L. This range is effective in controlling microbial growth, preventing the regrowth of pathogens, and ensuring the disinfection of the water supply as it travels through the distribution system.

A chlorine residual below 0.2 mg/L may not be sufficient to safeguard against microbial contamination, while levels exceeding 4.0 mg/L could lead to adverse taste and odor issues or corrosiveness in pipes. Therefore, the range of 0.2 to 4.0 mg/L strikes a balance between ensuring adequate disinfection and minimizing negative effects on water quality and infrastructure.

The other options, while they present specific range values, do not align with the standard guidance and best practices commonly adopted within the industry. Maintaining a chlorine residual appropriately helps to enhance the safety and quality of drinking water supplied to consumers.