The Clean Water Act Amendments of 1987 established the NPDES storm water program. The act called for implementation in two phases; Phase I addressed the most significant sources of pollution in storm water runoff. Phase II addresses other sources to protect water quality. The Phase II regulations were published in the December 8, 1999, Federal Register.
Summary of December 8, 1999, Storm Water Phase II Rule:
- Municipalities located in urban areas as defined by the Census Bureau are required to obtain NPDES permit coverage for discharges from their municipal separate storm sewer systems (MS4s). Municipalities located outside of urbanized areas may need to comply within 180 days notice or as determined by the NPDES Permitting Authority.
- Beginning on March 10, 2003, construction sites that disturb one acre or more are required to have coverage under the NPDES general permit for storm water discharges from construction site activities.
- Municipalities under 100,000 population will no longer be exempt from the construction site storm water requirements and the industrial storm water requirements effective March 10, 2003. (WWTPs 1.0 mgd or more will need a General Storm Water Permit for Industrial Activities)
- Definition of industrial storm water has been revised to expand the "no-exposure" exemption to all industrial categories except construction.
- Effective October 2, 2020, all Notice of Intents for Construction Sites must be filed through the USEPA's NeT tool. Please click on the Construction link for further information.