This data release codifies and attributes explanatory factors that could potentially impact groundwater quality at 49 groundwater sites used for domestic water supply in the Sacramento Metropolitan Domestic-Supply Aquifer Study Unit (SacMetro-DSA). Water quality from domestic groundwater sites in the SacMetro-DSA was assessed as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) program in 2017. The SacMetro-DSA study unit includes domestic wells within three Department of Water Resources defined groundwater subbasins; the North American, the South American, and the Cosumnes. Study design and site selection for the SacMetro-DSA study unit are detailed by Bennett and others (2019). Potential explanatory factors are attributed to domestic groundwater sites relating to: land use (percent agricultural, urban, and natural land use), underground storage and septic tank densities, hydrologic conditions (aridity index, elevation of the groundwater site), well construction (well depth, depth to the top of the open or perforated interval, well depth classification), groundwater age classification, and geochemical condition (groundwater redox classification, pH, dissolved oxygen). This data release contains a tab-delimited text file containing locations and potential explanatory factors for domestic groundwater sites in the SacMetro-DSA (Table 1). Additionally, an extensible markup language (XML) metadata file is included detailing process steps and references for attribution of potential explanatory factors to the groundwater sites. Bennett, G.L., V., Shelton, J.L., Watson, E., Johnson, T.D., and Jasper, M., 2019, Groundwater-quality data in the Sacramento Metro shallow aquifer study unit, 2017: Results from the California GAMA Priority Basin Project: U.S. Geological Survey data release Available at https://doi.org/10.5066/P9BPGEGH. These data support the following publications: Bennett, G.L. V, 2022, Status and Understanding of Groundwater Quality in the Sacramento Metropolitan Domestic-Supply Aquifer Study Unit, 2017: California GAMA Priority Basin Project: Geological Survey Scientific Investigations Report 2022–5021, 52 p., https://doi.org/10.3133/sir20225021.