Blue Plains Advanced Wastewater Treatment Plant, located at 5000 Overlook Ave SW, Washington, DC 20032, is the largest advanced wastewater treatment plant in the world. The facility is operated by the District of Columbia Water and Sewer Authority (DC Water). The plant opened in 1937 as a primary treatment facility, and advanced treatment capacity was added in the 1970s and 1980s. The effluent that leaves Blue Plains is discharged to the Potomac River and meets some of the most stringent permit limits in the United States.