There is a serious problem regarding the availability and quality of data on aspects as important as the status of aquifers in Latin America. Faced with this situation, it is urgent to elaborate simplified diagnostic methodologies. We propose a hydrogeological vulnerability index based on 32 universal indicators. After the application of qualitative multi-criteria techniques, we reduced the number of indicators to a total of three: land use, total dissolved solids, and groundwater levels. We identified an area of critical hydrogeological vulnerability associated with urban development. We conclude that the lack of data for the application of standardized models can be resolved with the selection of minimum key indicators relevant to each study area.