In recent years, many researchers have devoted their efforts to finding an objective measurement of sustainability by developing evaluation tools based on sustainability indices. These indexes not only reveal the current state of water resources in a given area but also contribute to the development and implementation of effective sustainable water management and decision-making. The great disadvantage of these indices is that for proper application, a number of variables are necessary and they are usually not available in data-scarce aquifers. This study was designed to evaluate sustainability in groundwater resource management in an aquifer in a semiarid zone, using readily available parameters and under a pressure-state-response framework. This methodology has been applied to an aquifer in Southeast Spain with satisfactory results, since the indicators that were evaluated reflect the two main problems that hinder sustainable resource management: the contamination of groundwater by intensive local farming; and the need for external inputs from other basins to alleviate water stress. Therefore, the methodology used can be replicated in other areas with similar characteristics to those of the case study.