Water-resources data for the 2002 water year for Pennsylvania consists of records of discharge and water quality of streams; contents and elevations of lakes and reservoirs; and water levels and water quality of ground-water wells. This report, Volume 3 contains (1) discharge records for 60 continuous-record streamflow-gaging stations, 5 partial-record stations, and 13 special study and miscellaneous streamflow sites; (2) elevation and contents records for 11 lakes and reservoirs; (3) water-quality records for 23 gaging stations and 33 ungaged streamsites; (4) water-level records for 23 network observation wells; (5) water-quality analyses at 28 special study ground-water wells; and (6) miscellaneous water-level measurements at 31 special study ground-water wells. Site locations are shown in figures throughout the report. Additional water data collected at various sites not involved in the systematic data-collection program are also presented. These data together with the data in Volumes 1 and 2, 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.