Western Washington Phase II Municipal Stormwater Permit
We develop and administer Clean Water Act National Pollutant Discharge Elimination System (NPDES) municipal stormwater permits in Washington. The Western Washington Phase II permit requires local governments to manage and control stormwater runoff so that it does not pollute downstream waters.
The current permit is effective Aug. 1, 2019, and expires on July 31, 2024.
Overview of permit timelines
View permit timelines for new
permittees. These timelines provide an overview of major deadlines for implementing permit requirements.
Annual reports for the calendar year are due by March 31 the following year.