What is the minimum chlorine residual required at the end of a water distribution system?

The minimum chlorine residual required at the end of a water distribution system is essential to ensure the safety and quality of the drinking water delivered to consumers. A chlorine residual of 0.2 mg/L is typically viewed as an acceptable standard in many regulatory frameworks. This level is sufficient to provide a safeguard against microbial contamination, ensuring that the water remains safe for consumption while also balancing the need to control tastes and odors associated with higher chlorine levels.

Achieving this minimum residual concentration helps maintain a barrier to pathogens throughout the distribution system, preventing any regrowth of harmful microorganisms that could occur if there is insufficient chlorine in the water. It reflects a balance between efficacy in disinfection and consumer acceptability, making sure the water supply is both safe and pleasant to use. Higher levels of chlorine can cause adverse taste and may lead to other water quality issues, which is why 0.2 mg/L is often the target for achieving an effective residual without compromising the water's sensory characteristics.