The California Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP) analyzed for per-and polyfluoroalkyl substances (PFAS) in groundwater samples collected from domestic and public drinking water supply wells in California. GAMA-PBP is a cooperative program between the U.S. Geological Survey and the California State Water Resources Control Board.

This data release contains data for samples collected from May 2019 through December 2022 and includes revisions to earlier data (Kent, 2021) that were either screened or removed after analysis of quality-control data. Please see the quality-control and other descriptions of the data in the processing steps in the xml file. Subsequent updates will include data for samples collected after December 2022. Data are also publicly available for download from Jurgens and others (2018).

The dataset consists of 4 tables. Table 1 lists the names and abbreviations of the twenty-eight PFAS constituents analyzed. Table 2 contains information about each site visited, including location and well depth information. Table 3 contains results for each PFAS constituent analyzed and includes quality-control sample results where applicable. Table 4 contains a list of every sample collected at each site and has a summary of all the PFAS detections for each sample.

This data release supercedes previous PFAS data release versions reported by Kent (2021). Version 2.0 of the previous data release (Kent, 2021) contained data for samples collected from May 2019 through June 2021. Data from Kent (2021) is available upon request from the authors of this data release.