Water-resources data for the 2003 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 185 gaging stations, stage and contents for 47 lakes and reservoirs, water quality for 45 stations and 13 partial-record stations, and precipitation data for 2 stations. Also included are 1 miscellaneous partial-record site and 1 crest-stage partial-record 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.