Currently the drinking water supply service system of the Metropolitan Area of Mexico City (ZMCM) faces serious problems in its operation, which generate highly negative impacts on the environmental, social and provider sectors of this system. Given the presence of climate change, we consider the possible scenario in which a decrease in average annual precipitation is generated in the area. To evaluate its impact on each of the sectors, the fuzzy cognitive map (FCM) associated with each of them was constructed. This framework allowed the study of a system that, in addition to being highly complex, the available information presented large ranges of uncertainty. Based on the resuls obtained, we present a mitigation measure for each sector, in order to provide efficient actions to decisions makers.