Under the Revised Total Coliform Rule, which indicator is used to assess potential contamination pathways into the distribution system?

• A. Coliform
• B. Escherichia coli
• C. Total Coliform
• D. Fecal coliform

Answer: (C)

Total Coliform is used as the indicator to assess potential contamination pathways into the distribution system. Its presence signals that the barriers protecting drinking water may be compromised, pointing to possible leaks, cross-connections, or other integrity issues that could allow contaminants to enter the system. Detecting total coliform triggers a sanitary survey and corrective actions to locate and fix these pathways. Fecal indicators like E. coli or fecal coliform would indicate actual fecal contamination, which is a different concern, and a generic term like coliform isn’t specific enough for this purpose.