Washington Reissues Phase 1 and Phase 2 MS4 Permits

On August 1, 2012, the Washington State Department of Ecology (Ecology) reissued three general National Pollutant Discharge Elimination System (NPDES) municipal stormwater permits:

• Phase I Municipal Stormwater General Permit (Phase I permit 2012 to 2013)
• Western Washington Phase II Municipal Stormwater Permit (WWA Phase II permit 2012 to 2013)
• Eastern Washington Phase II Municipal Stormwater Permit (EWA Phase II permit 2012 to 2014)

In accordance with 2012 legislation, Ecology reissued both Phase II permits without modification for a period of one (Western WA) and two (Eastern WA) years. Ecology also reissued the Phase I permit for a period of one year with limited changes.
In addition, Ecology reissued updated permits for the permit terms below:

• Phase I permit (2013 to 2018)
• Western Washington Phase II permit (2013 to 2018)
• Eastern Washington Phase II permit (2014 to 2019)

The National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General Permits cover discharges from municipal separate storm sewer systems (MS4s). The Phase I Municipal Stormwater Permit regulates the discharges from MS4s owned or operated by Clark, King, Pierce and Snohomish Counties; and the cities of Seattle and Tacoma (incorporated cities with a population over 100,000 and unincorporated counties with populations of more than 250,000 according to the 1990 census). The permit also applies to MS4s owned by public entities located in a Phase I city or county; including the Ports of Seattle and Tacoma.


Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.
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