During the triennium 2016-18, the two working groups contributed to the implementation strategy of the OECD Principles on Water Governance, focusing respectively on developing indicators and collecting and reviewing water governance stories. Effectiveness of water governance relates to the contribution of governance to defining clear sustainable water policy goals and targets at different levels of government, to implement those policy goals, and to meet expected objectives or targets. Efficiency of water governance relates to the contribution of governance to maximising the benefits of sustainable water management and welfare at the least cost to society.