The Segura River is about 350km long and flows from west to east discharging in to the Mediterranean on Spain’s east coast. The river passes through the entire region of Murcia which has the lowest annual rainfall in the European regions yet a population of over two million. The basin experiences an acute supply-demand imbalance as illustrated by the water scarcity index with demand exceeding the natural stream flow by 2.5 times; consequently water that is available in the river is of extremely poor quality thus further reducing resource availability. Thebasin is supplemented by an inter-catchment transfer from the Tajo river and desalination. Of a total demand of 1 900 million m3/yr, 87% is for agricultural use and 10% for municipal use. This project, implemented over a 10-year period, improves available resource through the capture and treatment of urban and industrial waste water flows and returning them for direct or indirect re-use in irrigation. A key element to the project’s success was the enaction of policy and legislation that enforces the “Polluter Pays” principle; this enabled waste water treatment and recovery to be operated on a cost recovery basis.