This paper assessed the economics of investing in suspended shade-cloth covers (SSCCs) in agricultural water reservoirs (AWRs) to reduce evaporation losses and save water for irrigation in arid and semi-arid areas. In particular, authors examine the use of SSCCs in the Segura River Basin (southeastern Spain). The decision to install a cover depends on the potential evaporation losses, reservoir characteristics, cover effectiveness, the value of water, filtration requirements, water salinity, government subsidies and the installation, operation and maintenance costs. The economic viability of the investment increases with the value of the saved water, i.e., with water scarcity, and is greater when water quality is poor. The farm-level decision to install a cover depends largely on the cost of purchasing water, when water is generally available, and the profit from increased crop production or enlarged farmlands, when water is scarce.