There is currently no common methodology for measuring irrigation subsidies at the national level. A concise set of defined parameters for the measurement of irrigation subsidies is needed to make any national estimates internationally comparable.

GSI has laid the foundations for the adoption of a common method for quantifying irrigation subsidies which draws on the main components of the Net Cost to the Supplier approach. This focuses on measuring identifiable government expenditures as reported in budget reports and official documentation.The methodology was used to estimate irrigation subsides in Spain. The study estimated subsidies to irrigated agriculture in Spain are between €906 million and €1.120 million per year based on conservative assumptions.This policy brief draws out the lessons learned from this study and provides recommendations on how to overcome some of the more general methodological challenges analysts face when quantifying irrigation subsidies, such as setting an appropriate price for water use and economic principles for valuing investments of capital for irrigation infrastructure. It also provides a number of specific recommendations for policy makers in Spain to help improve the level of publicly available information on subsidy programs.