The document gathers information about the current state of the treatment of the residual urban waters and it analyses the interest of its reuse in the planning of the water resources. The incessant increase of the water demands in contrast with the aberration of the available natural resources in areas of arid or semiaridclimate, along with an increasing social and institutional sensibility on the subject of environmental protection, are sufficient arguments to explain the great current interest for the treatment and reuse of the residual urban waters. In the document the principal systems are summed up for the treatment of residual waters and the current situation is checked at national, regional and provincial level. From this review the reality and the perspectives of Almeria are analyzed and there are proposed actions that will allow to relieve the scarcity of water resources, by means of the integration of the residual waters in the provincial hidrológical planning as an additional resource.