Historical groundwater and produced water chemistry data compiled for the San Ardo Oil Field and vicinity, Monterey County, central California

This digital dataset includes 255 samples from 41 groundwater wells and 271 samples of produced water from 143 sites (including 101 wells) located within 3 miles of the San Ardo Oil Field in Monterey County, central California. Historical geochemistry data were compiled from multiple data sources for selected water-quality indicators, major and minor ions, nutrients, and trace elements. Ancillary data in the form of top perforation or top of sample interval (petroleum wells), bottom perforation or bottom of sample interval (petroleum wells), well depth, or hole depth (water wells), land-surface (water wells) or reference point (petroleum wells) elevation at the well head, well location, and identifier information were also compiled.