Groundwater in the UAE's Quaternary aquifer has decreased significantly since 1969 due to intensive exploitation. Freshwater resources have dropped from 238 km3 to 10 km3, with brackish water replacing much of it. Total groundwater storage has only slightly decreased from 977 km3 to 922 km3. Continued exploitation may deplete freshwater in agricultural areas, leading to increased use of brackish water. Proper management of brackish water is crucial to prevent saltwater intrusion. Lessons from this study can benefit other arid regions facing similar water resource challenges.