Water-resources data for the 2004 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 2 contains discharge records for 134 gaging stations, stage and content records for 8 lakes and reservoirs, gage-height records for 8 stations, and water-quality records for 36 streamflow-gaging stations and 4 water-quality partial-record stations. Also included are data for 1 low-flow partial-record station, and 1 miscellaneous-measurement 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.