Water resources data for the 1991 water year for California consist of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 3 contains discharge records for 164 gaging stations, 3 crest-stage partial-record streamflow stations and 49 miscellaneous measurement stations; stage and contents records for 46 lakes and reservoirs; water quality records for 32 streamflow-gaging stations; and precipitation records for one station. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.