Originally this Act authorized the Surgeon General of the Public Health Service, in cooperation with other Federal, state and local entities, to prepare comprehensive programs for eliminating or reducing the pollution of interstate waters and tributaries and improving the sanitary condition of surface and underground waters. The original statute also authorized the Federal Works Administrator to assist states, municipalities, and interstate agencies in constructing treatment plants to prevent discharges of inadequately treated sewage and other wastes into interstate waters or tributaries. Since 1948, the original statute has been amended extensively either to authorize additional water quality programs, standards and procedures to govern allowable discharges, funding for construction grants or general program funding. Amendments in other years provided for continued authority to conduct program activities or administrative changes to related activities.