Outfall

An outfall is the discharge point of a storm drain or waste stream into a body of water. In the United Kingdom, the term may also apply to discharges from a "watercourse", which may be a river, stream or canal.¹

In the United States, point sources may not discharge pollutants to surface waters without a permit issued through the National Pollutant Discharge Elimination System (NPDES), as required by the Clean Water Act.² Most NPDES permits are issued by state environmental agencies. The U.S. Environmental Protection Agency (EPA) issues permits in some locations.³

Point sources include industrial facilities; service industries; municipal governments (particularly sewage treatment plants and stormwater outfalls); other government facilities such as military bases; and some agricultural facilities, such as animal feedlots.⁴