Phase II Municipal Stormwater Permits

Introduction to Phase II Municipal Stormwater Permits

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). The Washington State permits cover certain urbanized areas of Washington State. According to the rules, Phase II communities are jurisdictions that:

  • -Own and operate a storm drain system
  • -Discharge to surface waters
  • -Are located in urbanized areas
  • -Have a population greater than 1,000

The Department of Ecology developed maps of the census urbanized areas and jurisdictional boundaries. Ecology used these maps to identify potential Phase II jurisdictions. According to these maps, 104 towns, cities and counties are located with urban areas, and Ecology determined that these jurisdictions need to apply for Phase II stormwater permit coverage.

2005 Low Impact Development Manual (Element 13)


Western Washington Phase II Municipal Stormwater Permit (WWA Phase II permit 2012 to 2013)

The Phase II permit for western Washington applies to all regulated small municipal separate storm sewer systems. It covers at least 80 cities and 5 counties.
Phase II: Western WA Municipal Stormwater NPDES and State Waste Discharge General Permit
Appendix 1: Minimum Technical Requirements for New Development and Redevelopment
Appendix 2: Total Maximum Daily Load (TMDL) Requirements
Appendix 3: Annual Report Form for WW Phase II Cities, Towns and Counties
Appendix 4: Annual Report Forms for Secondary Permittees
Appendix 5: Notice of Intent (NOI) for Coverage (NPDES) Municipal Stormwater Permit
Appendix 6: Street Waste Disposal
Appendix 7: Determining Construction Site Sediment Damage Potential

Eastern Washington Phase II Municipal Stormwater Permit (EWA Phase II permit 2012 to 2014)

The Phase II permit for eastern Washington applies to all regulated small municipal separate storm sewer systems. It covers 20 cities and 8 counties.
Phase II: Eastern WA Municipal Stormwater NPDES and State Waste Discharge General Permit
Appendix 1: Minimum Technical Requirements for New Development and Redevelopment
Appendix 2: Total Maximum Daily Load (TMDL) Requirements
Appendix 3: Annual Report Forms for EW Phase II Cities, Towns and Counties
Appendix 4: Annual Report Forms for Secondary Permittees
Appendix 5: Notice of Intent (NOI) for Coverage (NPDES) Municipal Stormwater Permit