Water-resources data for the 1988 water year for Washington consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels of wells. This report contains discharge records for 202 gaging stations; stage only records for 6 gaging stations; stage and (or) contents for 38 lakes and reservoirs; water quality for 28 streamflow-gaging stations, and 9 ungaged streamsites; water levels for 77 observation wells; and water quality for 1 observation well. Also included are data for 13 crest-stage partial-record stations and 112 partial-record or miscellaneous streamflow stations. Locations of these sites are shown on figures 4a, 4b, 5, 6a, 6b, 35a, and 35b. 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 Washington.