Groundwater is vital for industrial, agricultural, and domestic needs, yet its over-extraction, particularly in Bangladesh for drinking and Boro rice production, is leading to diminishing aquifer levels. This study aims to estimate current groundwater use, assess the temporal fluctuations, and project future water table (WT) depth trends in the south-western area of Sylhet district in Bangladesh. The trends of the annual maximum and minimum depths of groundwater tables (GWTs) were determined and evaluated by using MAKESENS trend model. Using secondary data, the study found a thick confining layer in the region and noted a consistent decline in WT depths; rainfall however showed little effect on it. Certain areas like Fenchuganj, Balaganj, Bishwanath, and parts of Dakshin Surma upazila showed the most significant decrease as the maximum WT depths were above the suction limit, while the minimum WT depths were below the suction limit. From the variation analysis, the worst conditions were observed in Fenchuganj (fluctuating within 2–4.5 m), parts of Dakhin Surma upazila (fluctuating within 3–5 m), implying water scarcity in those wells. Predictions indicated some WT depths could double by 2050. Simulated data suggested that groundwater use might become impractical in these areas due to the significant decreasing trend observed. The study also examined Bangladesh’s groundwater policies to pinpoint potential improvements. Recommendations include on-farm water management, rainwater harvesting, soil-water conservation, and pre-extraction pumping tests for sustainable groundwater management.