This dataset contains the water-quality results from the testing of unfiltered water samples collected from 674 private wells in Connecticut for the analysis of arsenic and (or) uranium, using EPA method 200.8. All of the environmental water-quality data and georeferenced locations of the sampled wells were provided by the Connecticut Department of Public Health (CT-DPH). The water samples, collected from 2013 to 2015, were analyzed by the CT-DPH Laboratory in Hartford, CT. This dataset also contains information on the town and county location for each well and information on the geologic setting for each well. Latitude and longitude coordinate data are not provided in this data release in order to maintain the confidentiality of the well owner's identities.