"Groundwater sensitivity" is a useful concept for resource development and decision-making in water supply sector. A variety of methods have been deployed in the world to assess groundwater resources. Sensitivity of this resource depends on the demand for available resources, especially in the areas where the principal source of domestic water supply is groundwater. Continuous and adequate supplies of water from ground reserves are important to sustain agricultural, industrial and domestic requirements throughout the semi-arid regions of Sri Lanka. This paper describes an approach that investigates groundwater sensitivity in Puttalam district of Sri Lanka by evaluating the groundwater potential against the demand for groundwater. Five groundwater potential zones were identified through subjective weights assigned to interpreted thematic and derived topographic inputs according to their likely recharging and storage capacities. Three demand classes for ground water (high, moderate, and low) were derived based on the population distribution in the district. Overlay analysis of the two layers; groundwater potential zones and demand classes was performed to come up with four categories of groundwater sensitivity ranging from high to very low. Field measurements were then made using twelve randomly selected wells for each groundwater potential zone to verify the accuracy of derived groundwater potential zones. Observing results on mean specific yields of the derived potential zones, it is submitted that the accuracy of our proposed methodology should therefore be more than 70 percent. Based on these evidences, it can be concluded that the accuracy of the classification is suitable to be used for decision making as the best available information.