UN-Water analytical brief: Water-use efficiency

Water use efficiency has been highlighted as a key water indicator in the set of Sustainable Development Goals (SDGs). The method adopted by the SDG is evaluated and compared with specific sector approaches for evaluating the efficiency of freshwater use. The scale of the challenge for the SDG indicator is reviewed and the the range of evaluation methods that can be applied in the major water using sectors is illustrated. A case is made for looking in more detail at operational water accounting procedures in order to evaluate the scope for making the water use efficiency gains anticipated in SDG goal 6. The importance of measuring or estimating evaporative consumption of freshwater and the quantity and quality of return flows is stressed noting that the measurement of these variables in the water balance are often the most difficult to report accurately at scale.