Tracking the onset of inelastic (permanent) deformation is critical to quantifying the stress experienced by an aquifer system so that the effects of current groundwater extraction practices are put in the context of the sedimentary and geological histories of a region. However, the pre-consolidation stress is rarely known due to the lack of multi-decadal ground-based data. In this paper, we propose a new approach to track the onset and spatial evolution of inelastic deformation based on a 2003-2020 multi-sensor Interferometric Synthetic Aperture Radar time series analysis. Our study reveals that in central Iran, many locations that used to experience elastic (recoverable) deformation just a few years ago, are now deforming inelastically, leading to irreversible lowering of the ground surface and irreversible loss of aquifer storage. Lithologic data reveals that the total thickness of the drained clay layers controls the extent and timing of the observed inelastic deformation, while groundwater data confirms that the multi-decadal lowering of groundwater levels is driving the long-term compaction. These results highlight that we are now at or near a tipping point in time between sustainability and permanent damage to our underground water resources, emphasizing the fact that current decisions have the potential to change the natural resources landscape permanently.