Industrial stormwater

Industrial stormwater is runoff from precipitation (rain, snow, sleet, freezing rain, or hail) that lands on industrial sites (e.g. manufacturing facilities, mines, airports). This runoff is often polluted by materials that are handled or stored on the sites, and the facilities are subject to regulations to control the discharges. In the United States, facilities that discharge industrial stormwater to surface waters must obtain a permit under the National Pollutant Discharge Elimination System (NPDES), pursuant to the Clean Water Act. Stormwater permit regulations issued by the United States Environmental Protection Agency (EPA) govern the permit process. EPA published its "Phase I" stormwater rule, which covers industrial dischargers, in 1990. Most stormwater permits in the U.S. are issued by the agencies in 47 states that have been given authority by EPA. EPA regional offices issue the stormwater permits in the remaining parts of the country. EPA published its Multi-Sector General Permit (MSGP) initially in 1995 to govern how industrial stormwater should be managed, and periodically it has updated and reissued the permit.