Water-resources data for the 1998 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 172 gaging stations, stage and contents for 43 lakes and reservoirs, and water quality for 36 stations. Also included is 1 crest-stage partial-record station and 3 miscellaneous partial-record site. 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.