What is the acceptable coliform level indicated by AWWA C651 following a disinfection procedure?

The acceptable coliform level indicated by AWWA C651 following a disinfection procedure is zero CFU/mL. This standard reflects the requirement for drinking water systems to ensure that pathogenic microorganisms are effectively eliminated during the disinfection process. The presence of coliform bacteria, particularly E. coli, can indicate potential contamination with fecal material and the possible presence of harmful pathogens.

Achieving a coliform level of zero signifies that the disinfection process has been successful in eliminating these organisms, thus ensuring the safety and microbiological quality of the water supply. Ensuring there are no detectable coliforms post-disinfection aligns with public health objectives to prevent waterborne diseases and maintain consumer confidence in water quality. Therefore, a zero CFU/mL standard is not only a best practice but also a crucial component of effective water management and public health protection.