Based on case studies of at least four water recycling projects in northern California counties, this project will examine how scientific uncertainty, economic incentives, and regulatory pressures influence decisions to implement water recycling projects for agricultural irrigation and ecosystem restoration. Our explanation of the decision-making process incorporates uncertainty in scientific knowledge and considers the effect of higher and lower levels of scientific certainty on perceptions of risk and policymaking. Our ultimate objective is to produce statements about engineering best practices and public policy recommendations to realize the potential of recycled water projects.