To support the concept of One Water, utilities and municipalities are better integrating water resources and expanding on traditional pretreatment programs. These innovations can provide a meaningful and cost-effective opportunity to support One Water initiatives. However, no study has been conducted to fully assess the opportunities and the barriers to expanding pretreatment practices for supporting One Water initiatives. This project will evaluate pretreatment programs and their relationship to One Water goals, identify regulatory requirements impacting pretreatment programs, including factors that drive or inhibit innovation, review pretreatment programs and their relationship with the operations of publicly owned treatment works (POTWs) and the commercial/industrial user community, and identify potential opportunities to leverage pretreatment programs in implementing One Water strategies. A guidance manual will outline best practices, case studies, and the results of a national survey of POTWs.