What is the optimum pH range for chlorine water solution disinfection?

The optimum pH range for chlorine water solution disinfection is typically found between 7 and 8. Within this pH range, chlorine remains effective as a disinfectant while also minimizing the formation of harmful by-products, such as chloramines. When chlorine is added to water, it can exist in different forms depending on the pH level; the higher the pH, the more likely chlorine will form less effective chloramines rather than the more potent hypochlorous acid.

At a pH of around 7 to 8, hypochlorous acid predominates, providing superior microbial kill rates and overall disinfection efficacy. Disinfecting at this optimal pH helps to ensure that pathogens are effectively neutralized without the introduction of excessive chlorine resistance or harmful side effects that can occur at lower or higher pH levels. This range strikes a balance where chlorine can perform optimally while protecting water quality and safety.