What is the purpose of chlorine residual in the water distribution system?

The purpose of chlorine residual in the water distribution system is primarily to kill remaining bacteria. Chlorine is widely used as a disinfectant in water treatment because it is effective in eliminating harmful microorganisms that can cause waterborne diseases. When chlorine is added to the water supply, it reacts with these microbes and helps ensure that they are destroyed before the water reaches consumers.

Maintaining a chlorine residual in the distribution system also serves as a safeguard against potential contamination that can occur after treatment but before consumption. It acts as a barrier, preventing the regrowth of bacteria and other pathogens as water travels through the pipes, which can occur due to various environmental factors or if the water becomes stagnant.

While there are other potential benefits to chlorine—such as improving taste or contributing to odor control—these are not its primary function when it comes to water safety. Similarly, chlorine does not play a role in stabilizing water temperature. The focus is primarily on disinfection and maintaining the microbiological integrity of the water supply.