This book addresses multilevel governance challenges in water policy implementation and identifies good practices for coordinating water policy across ministries, between levels of government, and across local actors at the subnational level. Water Governance in OECD Countries assesses the main "coordination gaps" in terms of policymaking, financing, information, accountability, objectives, and capacity building and provides a platform of existing governance mechanisms to bridge them. Based on an extensive survey on water governance, the book provides a comprehensive institutional mapping of roles and responsibilities in water policymaking at national and subnational levels in seventeen OECD countries. It concludes with preliminary multilevel governance guidelines for integrated water policy.