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Generic groundwater flow simulation models show that geohydrologic factors-fracture types, fracture geometry, and surficial materials-affect the size, shape, and location of source-water areas for bedrock wells. In this study, conducted by the U.S. Geological Survey in cooperation with the Connecticut Department of Public Health, groundwater flow was simulated to bedrock wells in three settings-on hilltops and hillsides with no surficial aquifer, in a narrow valley with a surficial aquifer, and in a broad valley with a surficial aquifer-to show how different combinations of geohydrologic factors in different topographic settings affect the dimensions and locations of source-water areas in Connecticut. Three principal types of fractures are present in bedrock in Connecticut-(1) Layer-parallel fractures, which developed as partings along bedding in sedimentary rock and compositional layering or foliation in metamorphic rock (dips of these frac-Simulation of GroundWater Flow to Assess Geohydrologic Factors and their Effect on Source-Water Areas for Bedrock Wells in Connecticut (conceptual model C). When a preferred orientation of hydraulic conductivity was assumed, modeled source-water areas were elongated in the direction of the principal hydraulic conductivity. Model C is reasonable because that model estimates a direction of higher hydraulic conductivity in the strike direction of layering, as expected, and the available hydrologic data support it. Model C also calculated the most difference in the estimated source-water areas; therefore, it is important to know if an aquifer has a preferred orientation of hydraulic conductivity.