What are nutrient cycles, and why do they matter for the environmental, economic, and social resilience of cities and regions? This publication introduces the concept of circular sanitation and explains why closing nitrogen and phosphorus cycles is essential to reducing pollution, strengthening resource security, and supporting sustainable local food systems. Drawing on examples and case studies from across Europe, the guidelines present practical policies, governance approaches, and implementation measures that local and regional governments can use to transition towards circular sanitation systems. Developed within the Horizon Europe project P2GreeN, the publication provides actionable recommendations, stakeholder engagement strategies, and concrete tools to help make circular nutrient management a reality.