This document (the Economic and Benefits Analysis or EA) provides analytical support for development of EPA's Proposed Existing Facilities Rule, which implements Clean Water Act (CWA) 316(b) requirements governing cooling water intake structures at certain existing power producing facilities (Electric Generators) and manufacturing facilities (Manufacturers). These requirements would apply to existing Electric Generators and Manufacturers (existing facilities) with cooling water intake structures that are designed to withdraw two million gallons per day (MGD) or more of water from rivers, streams, lakes, reservoirs, estuaries, oceans, or other waters of the United States for cooling purposes. The national requirements, which will be implemented through National Pollutant Discharge Elimination System (NPDES) permits upon promulgation, are based on the best technology available to minimize the adverse environmental impact associated with the use of cooling water intake structures.