Water samples were collected from 14 production wells and 15 private wells in central New York from August through December 2012 in a study conducted by the U.S. Geological Survey in cooperation with the New York State Department of Environmental Conservation. The samples were analyzed to characterize the groundwater quality in unconsolidated and bedrock aquifers in this area. Fifteen of the wells are finished in sand-and-gravel aquifers, and 14 are finished in bedrock aquifers. Six of the 29 wells were sampled in a previous central New York study, which was conducted in 2007. Water samples from the 2012 study were analyzed for 147 physiochemical properties and constituents, including major ions, nutrients, trace elements, radionuclides, pesticides, volatile organic compounds, dissolved gases (argon, carbon dioxide, methane, nitrogen, oxygen), and indicator bacteria. Results of the water-quality analyses are presented in tabular form for individual wells, and summary statistics for specific constituents are presented by aquifer type. The results are compared with Federal and New York State drinking-water standards, which typically are identical. The results indicate that the groundwater generally is of acceptable quality, although for all of the wells sampled, at least one of the following constituents was detected at a concentration that exceeded current or proposed Federal or New York State drinking-water standards: color (2 samples), pH (7 samples), sodium (9 samples), chloride (2 samples), fluoride (2 samples), sulfate (2 samples), dissolved solids (8 samples), aluminum (4 samples), arsenic (1 sample), iron (9 samples), manganese (13 samples), radon-222 (13 samples), total coliform bacteria (6 samples), and heterotrophic bacteria (2 samples). Drinking-water standards for nitrate, nitrite, antimony, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, silver, thallium, zinc, gross alpha radioactivity, uranium, fecal coliform, and Escherichia coliwere not exceeded in any of the samples collected. None of the pesticides or volatile organic compounds analyzed exceeded drinking-water standards. Methane was detected in 11 sand-and-gravel wells and 9 bedrock wells. Five of the 14 bedrock wells had water with methane concentrations approaching 10 mg/L; water in one bedrock well had 37 mg/L of methane.