Since 1932 the United States Geological Survey in cooperation with the New York Water Power and Control Commission, the Nassau County Department of Public Works, the Suffolk County Water Authority, and the Suffolk County Board of Supervisors has conducted studies dealing with the occurrence, movement, quantity, quality, and temperature of ground water on Long Island. Also, as a part of three investigations, data on the withdrawals by pumpage for public water supply are assembled an analyzed. Previously, pumpage records for periods from 1904 through 1946 have been released.