At the End of the Pipe: Change and Continuity in Sanitation Systems in Mexico

Until recently, in many Mexican cities, one of the ways of treating urban wastewaters was to reuse them for irrigation in agricultural areas. Thus, at the very limit of the sewage system another network was formed in a particular socio-technical configuration which allowed Mexican farmers to gather as much water as possible to irrigate the soil. At present, the rise of a generalised concern for the environment and a more restrictive legislative framework make the treatment of wastewater obligatory. This paper analyzes the dynamics at work in the transition process from a model of wastewater management based on recycling in agriculture to a new model which is more efficient both in health and environmental terms. The addition of treatment plants to the urban sewage system has had many impacts, not only on the technical processing and on the quality of the water, which have improved urban environmental conditions, but, at the same time, on the modalities of access to the system and of wastewater distribution, and on the local power relations constituted around water.