In recent years, there have been substantial changes in the factors that affect a growth in water demand and in the framework and constraints for providing the solutions that will meet these demands. Requirements are growing at the speed of light, whereas solutions are being established at a snail's pace.
In the past, there was considerable headroom where guaranteeing the supply were concerned, but unfortunately the leeway that once existed is being rapidly eroded away. The procedures for facing up to these challenges and new frameworks and problems require new ways of analysis and approach to the solutions. This paper explains the factors that are determinants for the requirements and their solutions, provides figures of reference for the Autonomous Region of Madrid supply system in Spain (5.5 million inhabitants) and the lines that are being followed to reduce the uncertainties involved in demand prediction, so that planning investment in infrastructures can be adapted and water can be managed in a way that is consistent with a set of factors that determine the eventual water consumption as a result of a profound interaction between territorial, social, environmental and economic factors.