The subtle equilibrium between supply and demand of freshwater is constantly changing due to anthropogenic activities and shifts in land use and climate. These freshwater resources are crucial for food and water security, and the sustainability of natural and managed systems. The spatial-temporal properties of groundwater are often overlooked, despite these subsurface reservoirs being linked to aboveground water use and ecosystem processes. In this study, we assessed the spatial-temporal changes of water table depth in the conterminous United States (U.S.) over the last three decades (1989-2019). National Ground-Water Monitoring Network water table depth data were paired with climate and terrain features. Interpolated maps were created by combining machine learning (i.e., gradient boosted regression trees) with traditional interpolation methods (i.e., Kriging). Water table depth is shallower in the eastern U.S., as compared to western U.S., except for high elevation locals which consistently had deeper water tables. The overall change in depth to water table for the conterminous U.S. was ~1m indicating that on average the water is getting deeper. Of the 56 aquifer systems, 41 are in areas where the water table has gotten deeper. These results highlight current “hotspots” of possible depletion where water management efforts should focus. Management of this crucial resource is essential for mitigating negative impacts of depletion, which may ultimately feedback further amplifying changes in climate.