What must be checked in a positive Total Coliform sample?

In the context of water treatment, a positive Total Coliform sample is a significant indicator of potential contamination that can pose a health risk to humans. Specifically, when a Total Coliform test returns positive, it is crucial to check for Fecal Coliform or E. coli presence. This is because Total Coliforms include a broad range of bacteria, many of which are not harmful. However, the presence of Fecal Coliforms, particularly E. coli, indicates fecal contamination and the potential presence of pathogens that can lead to waterborne diseases.

Confirming the presence of Fecal Coliform or E. coli is essential for assessing the safety of the water supply. Their detection signals that the water may contain harmful microorganisms and necessitates immediate action to ensure public health and safety, such as further testing, treatment, or issuing a boil water advisory.

The other options, while relevant in water quality testing, do not directly address the immediate health concerns raised by a positive Total Coliform sample. Turbidity can affect treatment processes but does not indicate fecal contamination. Free Chlorine levels are important for disinfection but do not assess the presence of harmful bacteria. Total Dissolved Solids (TDS) relate more to water quality