This dataset contains the trace elements, cations, anions, disinfection by-products, per- and polyfluoroalkyl substances (PFAS), pharmaceutical and pesticide concentration results for the tapwater study conducted in California, November, 2020 through May, 2021. Trace elements, cations and anions were analyzed at the U.S. Geological Survey Redox Chemistry Laboratory in Boulder, Colorado. The disinfection by-product compounds were analyzed at the U.S. Geological Survey Organic Chemistry Research Laboratory in Sacramento, California. Concentration results for PFAS, as well as surrogate percent recovery information, were analyzed at the National Water Quality Laboratory (NWQL) in Denver, Colorado, and were added in version 2.0. Concentration results for pharmaceutical and pesticide compounds, analyzed at the NWQL, were added in version 3.0. Version 3.1 corrects a single barium value from 710 micrograms per liter (ug/L) to 71.0 ug/L, at site TW2020 CABRG 034.