This project provides a quantitative understanding of the value of barriers, such as chlorine and chloramine, along with main break repair procedures and operational practices, in preventing potential customer exposure to pathogens associated with main breaks and subsequent repairs. This project also identified, from a utility perspective, the primary factors that must be understood in order to manage the risk to customers from exposure to pathogens. In addition to the final report, a Field Pocket Guide was published to help field crews who are doing repairs to remember and implement good practices during repair of water main breaks. The Field Pocket Guide may also be useful in utility training programs for crews involved in these activities. Printed copies of the final report and Field Pocket Guide can be ordered as 4307a. Additionally, the Field Pocket Guide can be ordered separately as 4307b. Lastly, a Fact Sheet was developed to highlight the key findings (available under Project Resources/Project Papers). Research partner: DWI. Published in 2014.