What is a common method for measuring the effectiveness of chlorination?

Measuring residual chlorine levels in the water is a widely accepted method for determining the effectiveness of chlorination. When chlorine is added to water for disinfection, a portion of the chlorine reacts with contaminants, while some remains in the water as residual chlorine. This residual is the amount of chlorine that continues to provide disinfection as water moves through the distribution system.

By testing for residual chlorine, operators can ensure that sufficient chlorine is present to effectively kill bacteria and prevent microbial regrowth. Consistent monitoring of residual chlorine levels helps confirm that the chlorination process is functioning properly and that the water remains safe for consumption.

Other options, such as assessing turbidity, measuring temperature, or analyzing pH, provide useful information regarding overall water quality but do not specifically indicate the effectiveness of chlorination. Turbidity can reflect particle concentration, temperature can affect chemical reactions, and pH can influence chlorine's effectiveness, but none directly measure the disinfecting presence of chlorine itself.