Laura M. Bexfield MaryLynn Musgrove Bruce D. Lindsey Paul E. Stackelberg Jeannie R. B. Barlow Leslie A. DeSimone Justin T. Kulongoski James A. Kingsbury Joseph D. Ayotte Brandon J. Fleming Kenneth Belitz Terri Arnold 2017 <p>Groundwater-quality data were collected from 559 wells as part of the National Water-Quality Assessment Project of the U.S. Geological Survey National Water-Quality Program from January through December 2014. The data were collected from four types of well networks: principal aquifer study networks, which are used to assess the quality of groundwater used for public water supply; land-use study networks, which are used to assess land-use effects on shallow groundwater quality; major aquifer study networks, which are used to assess the quality of groundwater used for domestic supply; and enhanced trends networks, which are used to evaluate the time scales during which groundwater quality changes. Groundwater samples were analyzed for a large number of water-quality indicators and constituents, including major ions, nutrients, trace elements, volatile organic compounds, pesticides, radionuclides, and some constituents of special interest (arsenic speciation, chromium [VI] and perchlorate). These groundwater-quality data, along with data from quality-control samples, are tabulated in this report and in an associated data release.</p> application/pdf 10.3133/ds1063 en U.S. Geological Survey Groundwater-quality data from the National Water-Quality Assessment Project, January through December 2014 and select quality-control data from May 2012 through December 2014 reports