Regulation & law · 08/12/1999Updated: 10/17/2026 · 1 min read

US EPA Expands National Pollutant Discharge Elimination System Regulations to Address Storm Water Discharges from Small Municipal Separate Storm Sewer Systems and Construction Sites

The US Environmental Protection Agency (EPA) has issued new regulations expanding the National Pollutant Discharge Elimination System (NPDES) storm water program to include small municipal separate storm sewer systems (MS4s) and construction sites that disturb one to five acres, while excluding certain sources from the national program based on their environmental impact.