The chapter provides insights into the overall cost of water resources management, across junctions and institutions, examines the various sources of financing, and summarises key studies on projectedfuture costs. Based on the OECD’s framework for financing water resources management, it also identifies opportunities to improve financial sustainability. Particular attention is paid to the application of the “beneficiary pays” and “polluter pays ” principles, as well as incentives for cost efficiency and the fair allocation of costs across water users.