Strategies for Managing Total Coliform and E. coli in Distribution Systems

The objective of this project was to develop a practical guide to help utilities manage and develop response strategies to total coliform and E. coli occurrences in the distribution system. This guide will help utilities identify the cause(s), evaluate the significance of, and respond to positive coliform and E. coli events. Guidance is provided to assess the potential for treatment breakthrough, contamination of the distribution system associated with operations and maintenance practices, and regrowth. The guidance has been developed to assist with Level 1 and Level 2 Assessments that have been proposed under the Revised Total Coliform Rule.