Municipal Stormwater Permit jurisdiction areas for Phase I and Phase II permits, issued by the Washington State Department of Ecology. The Phase I permit regulates discharges from municipal separate storm sewers owned or operated by Clark, King, Pierce and Snohomish Counties, and the cities of Seattle and Tacoma. The Phase II Municipal Stormwater Permit rule extends the coverage of the National Pollutant Discharge Elimination System (NPDES) program to certain "small" municipal separate stormwater sewer systems (MS4s). These permit areas incorporate 2019 updates to incorporated City boundaries and unincorporated Urban Growth Areas (UGA) as defined by the Growth Management Act, as well as 2010 Census extents for urbanized areas adjacent to permitted cities and UGAs. This dataset was last updated in 2019. The current permit is effective Aug. 1, 2019, and expires on July 31, 2024.