What does "chlorine residual" refer to in a water distribution system?

Chlorine residual refers specifically to the amount of chlorine that remains in the water after it has gone through the disinfection process. This residual is crucial for ensuring that the water remains safe for consumption and free from harmful microorganisms as it travels through the distribution system. Maintaining an adequate chlorine residual helps to prevent recontamination and prolongs the effectiveness of the disinfection process.

The presence of chlorine residual is monitored to ensure that it is at a safe and effective level, which means that it must be sufficient to inhibit bacterial growth but not so high as to pose a health risk to consumers. This balance is essential in maintaining water quality throughout the distribution network.