Water resources data for the 1975 water year for Connecticut consist of records of stage, discharge, and water quality of streams; contents and water quality of lakes and reservoirs; and water levels and water quality of ground water. This report contains discharge records for 56 gaging stations; tidal volume for 1 gaging station; stage only records for 3 tidal-gaging stations; contents for 36 lakes and reservoirs; water quality for 16 gaging stations, 39 partial-record flow stations, 3 lakes, 2 tidal stations, and 4 wells; and water levels for 27 observation wells. Also included are data for 65 crest-stage partial-record stations and 55 low-flow partial-record stations. Additional water data were collected at various sites, not part of the systematic data collection program, and are published as miscellaneous measurements. Locations of hydrologic stations are shown on figures 1 and 2. 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 Connecticut.