Water utilities of all sizes face significant challenges, and there are many forms of, and opportunities for, mutually beneficial partnerships between utilities that can help them address these challenges. Despite the considerable benefits offered by regional collaborations, the number of such agreements has been fairly limited. The obstacles (perceived and real) to partnerships have limited the extent to which utility partnerships have manifested. Nonetheless, there are several successful formal and informal partnerships that can serve as valuable illustrations and guides for how utility partnerships can be forged within the political, legal, fiscal, regulatory, and other institutional systems that need to be considered. This project summarizes existing work to describe partnership opportunities, and uses a deliberate prioritization and scoping process to identify gaps in existing information, collect new partnership examples, and revise or expand existing materials to help fill those gaps to increase the development of successful partnerships. Published in 2019.