What is a key consideration when disinfecting a new or repaired water main?

Maintaining a minimum chlorine residual during the disinfection process of a new or repaired water main is essential to ensure the effectiveness of the disinfection and to protect against pathogen regrowth. Chlorine serves as a powerful disinfectant, and its residual is an indicator that the water is safe for consumption. By ensuring that a minimum chlorine residual is maintained, operators can confirm that the water has been adequately disinfected and that any harmful microorganisms have been eradicated.

This practice helps to prevent contamination from any residual pathogens that may have been introduced during construction or repair activities. The presence of chlorine residual also serves as a safeguard during the distribution process, ensuring that any potential recontamination does not compromise water quality before it reaches consumers.

In contrast, immediate use after treatment may not be safe if a proper residual hasn’t been confirmed, while the other options pertaining to chlorine concentration and isolation of pipes do not address the ongoing requirement for residual disinfection capacity throughout the system. Therefore, maintaining a minimum chlorine residual is crucial for ensuring the safety and quality of the water being delivered.