Achieving cost recovery targets, developing water pricing and trading mechanisms, clarifying water entitlements and changing institutional arrangements, need to be underpinned by more and reliable information. Encouraging examples are the monitoring of minimum water flow rates in rivers as part of environmental planning, and comprehensive river basin assessments being undertaken in a number of countries. However, considerable information and knowledge gaps still remain. This encompasses data on the sources of water used, improved calculations of the physical and economic efficiency of water use in agriculture, and a better understanding of the links between on-farm water use and off-farm environmental impacts.