In this paper, the comprehensive approach provided by the Life Cycle Assessment (LCA) in water management is shown. It includes the LCA of the diverse water supply alternatives within a region but also the LCA of further water uses. The case study is the Segura Basin, a dry area in the southeast of Spain with important water demands. Thus, external alternatives like water transfers and desalination are required to partly balance the reduced natural water availability. The paper firstly shows the environmental impacts of water supply alternatives, depending on its contribution to the water balance in the watershed. Secondly, the LCA of water use in that water stressed area is also analysed, in order to compare both impacts. The target is to analyse if alternatives reduce the global impact of water supply and to compare that damage with that derived from water use. Both LCA approaches are integrated by using the Eco-Indicator 99 method.