Water resources data for the 1983 water year for Pennsylvania consist of records of discharge and water quality of streams; contents of lakes and reservoirs; and water levels, and water quality of ground-water wells. This volume contains records for water discharge at 84 stations; contents at 13 lakes and reservoirs, water quality at 18 gaging stations; and water levels at 26 network observation wells. Also included are data for 12 crest-stage, 98 low flow, and 3 water-quality, and 85 ground water-quality partial-record stations. Locations of these sites are shown on figures 7-10. Additional water data were collected at various sites not involved in-the systematic data-collection program and are published as miscellaneous measurements and analysis. These data together with the data in Volumes 1 and 3 represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Pennsylvania.