Mary Ray 2010 The U.S. Geological Survey, in cooperation with Federal, State, and local agencies, obtains a large amount of data pertaining to the groundwater resources of California each water year (October 1-September 30). These data constitute a valuable database for developing an improved understanding of the water resources of the State. This Fact Sheet serves as an index to groundwater data for Water Year 2009. The 2 page report contains a map of California showing the number of wells (by county) with available water-level and water-quality data for Water Year 2009 (fig. 1) and instructions for obtaining this and other groundwater information contained in the databases of the U.S. Geological Survey, California Water Science Center. From 1985 to 1993, data were published in the annual report 'Water Resources Data for California, Volume 5. Ground-Water Data'; prior to 1985, the data were published in U.S. Geological Survey Water-Supply Papers. application/pdf 10.3133/fs20103031 en U.S. Geological Survey Availability of Groundwater Data for California, Water Year 2009 reports