The Department of Health (DOH) issued the National Pollutant Discharge Elimination System (NPDES) Permit No. HI S000001 (MS4 NPDES Permit) to the State of Hawaii, Department of Transportation, Highways, Oahu District (DOT-HWYS). The MS4 NPDES Permit requires the DOT-HWYS Storm Water Management Program (SWMP) to reduce the discharge of pollutants from the MS4 to the maximum extent practicable (MEP), and is the backbone of HDOT efforts to continue reducing pollutants in storm water runoff.

The MS4 NPDES Permit became effective on September 1, 2020, and will expire at midnight, August 31, 2025. Read more about this on our About Page.

Download MS4 NPDES Permit