NPDES

NPDES — the National Pollutant Discharge Elimination System — is the EPA permitting program (often delegated to a state agency, such as CDPHE in Colorado) that regulates the discharge of pollutants, including construction stormwater, into waters of the United States.

Most construction sites over one acre need NPDES permit coverage, which requires a Stormwater Pollution Prevention Plan (SWPPP) documenting the BMPs — including concrete washout containment — the project will use.