Domestic water demand management: implications for Mexico City

Abstract

The City of Mexico, one of the largest and most crowded megalopolises in the world, is struggling to provide enough water to an ever-increasing population. Although cuts have been common for a number of years, the crisis has lately extended, affecting well over 5 million inhabitants. The problem is only expected to get worse, compounded by the following factors:(1) Main supply relies on overexploited aquifers and distant external sources.(2) As the ancient city was constructed on top of a lake, parts of the metropolis are gradually sinking. In consequence, wastewater discharges have to be pumped out.(3) About 40% of all the incoming liquid is lost in leaks, due to an old piping system and seismic activity.In light of this complex crisis, the authorities have failed to find an adequate solution, since the aim has traditionally been to find new external sources, that is, a supply-side strategy. This article analyses a different approach, focused on demand-side management, and discusses alternatives from a quantitative and qualitative point of view, using the retrofitting of sanitary facilities as an example. Successful experiences in other cities are presented, along with a discussion of the main obstacles to overcome. It is concluded that the potential for such strategies are considerable in Mexico City, but adequate financial stimulus for conservation are urgently needed, along with a change of perspective on behalf of government authorities, to focus on demand reduction rather than on costly, and in most cases impractical, augmentation of supply.