Watershed investment programs offer promising pathways to securing safe drinking water. But what does it take to establish and grow a successful watershed investment program? Program investors and practitioners are looking for guidance and ideas on how to build a program that works for their own context. This report addresses this need by compiling experiences and lessons from 13 watershed investment programs from across the United States. Based on a 3-year comparative case study analysis, it serves as a roadmap to guide utilities and communities as they work together to protect precious source waters.