Groundwater resources are crucial sources of freshwater, underscoring the importance of comprehensive aquifer health assessment for improved management and sustainable utilization. In this study, a novel index for assessing groundwater stress, termed the revised groundwater footprint index, was developed. The new index was compared with earlier versions in a case study of the Yom and Nan river basins in Thailand. The primary strength of the new index lies in its capacity to reduce uncertainties in groundwater stress estimation by avoiding double-counting of contaminated areas, particularly in overlapping zones, and by addressing complexities associated with multiple pollutants. An earlier-version index, known as the integrated groundwater footprint index, calculated groundwater stress in the Yom and Nan river basins as 2.75 and 2.13, respectively, significantly exceeding the maximum permissible limit of 1. In contrast, the revised groundwater footprint index yielded much lower stress values of 0.69 and 0.63 in the Yom and Nan river basins, respectively, which more accurately reflected actual conditions. The novel index can serve as a valuable tool for enhanced assessment and management of groundwater resources, supporting progress toward United Nations Sustainable Development Goal 6.4 (Water Stress).