Annual reports to Ecology for the NPDES Municipal Stormwater Permit

Under the terms of King County's Phase I Municipal Stormwater NPDES Permit , the County must submit annual reports to the Washington State Department of Ecology (Ecology).

For the recently reissued permit (2007-2011), the Annual Report submittal package to Ecology consists of two parts:

• The annual report spreadsheet, attachments and appendices, which cover the previous calendar year (found below).
• The upcoming calendar year's Stormwater Management Program (SWMP) document.

2020 annual report 

2019 annual report

Phase I Municipal Stormwater NPDES Permit

• MS4 Annual Report Phase I 

• Appendices 

2018 annual report covering partial year 2017

Phase I Municipal Stormwater NPDES Permit

• MS4 Annual Report Phase I (1 Mb)

• Appendices (9.5 Mb)

2017 annual report covering partial year 2016

Phase I Municipal Stormwater NPDES Permit

• MS4 Annual Report Phase I (1 Mb)
• Appendices (9.7 Mb) 

2016 annual report covering partial year 2015

Phase I Municipal Stormwater NPDES Permit

• MS4 Annual Report Phase I (45 Kb)
• Appendices (8.6 Mb) 

2015 annual report covering partial year 2014

Phase I Municipal Stormwater NPDES Permit

• MS4 Annual Report Phase I (83 Kb)
• Appendices (2.4 Mb) 

2013 annual report covering partial year 2013

Phase I Municipal Stormwater NPDES Permit - Stormwater Monitoring Reports covering partial year 2013

S8.D Stormwater Monitoring -

• Stormwater Characterization Monitoring Report (2.7 Mb)
• Appendices A-E (22.9 Mb)  

2013 annual report covering calendar year 2012

Annual Report (PDF 3.2 Mb) SWMP not included, see link above. Monitoring reports not included, see links below.

Phase I Municipal Stormwater NPDES Permit - Stormwater Monitoring Reports covering calendar year 2012

S8.D Stormwater Monitoring -

• Stormwater Characterization Monitoring Report (2.7 Mb)
• Appendices A-E (22.9 Mb)

S8.D Stormwater Monitoring -

• Stormwater Characterization Monitoring Report (2.7 Mb)
• Appendices A-E (22.9 Mb)  

Archived annual reports

2012 annual report covering calendar year 2011

Annual Report (PDF 4.3 Mb) SWMP not included, see link above. Monitoring reports not included, see links below.

New in 2012 - Phase I Municipal Stormwater NPDES Permit - Stormwater Monitoring Reports

S8.D Stormwater Monitoring -

• Stormwater Characterization Monitoring Report

S8.E Targeted Stormwater Management Program Effectiveness Monitoring

• Roadside Ditch Stormwater Treatment Study Report
  • Appendix A and B, Storm Summary Figures and Quality Assurance/Quality Control (930 Kb)
  • Appendix C and D, Analytical Result Charts and BMP Plan Drawings (21.5 Mb)
  • Appendix E and F, Photographs and References (4.9 Mb)

S8.F Stormwater Treatment and Hydrologic Management Best Management Practice (BMP) Evaluation Monitoring

• BMP Effectiveness Monitoring Report
• Flow Reduction BMP Monitoring Report

2011 annual report covering calendar year 2010

Annual Report (PDF 6.1 Mb) SWMP not included, see link above. Monitoring reports not included, see links below.

New for 2011 - Phase I Municipal Stormwater NPDES Permit - Stormwater Monitoring Reports

S8.D Stormwater Monitoring

• Stormwater Characterization Monitoring Report

S8.E Targeted Stormwater Management Program Effectiveness Monitoring

• Roadside Ditch Flow Control Study Report
• Roadside Ditch Water Quality Study Report

S8.F Stormwater Treatment and Hydrologic Management Best Management Practice (BMP) Evaluation Monitoring

• BMP Effectiveness Monitoring Report
• Flow Reduction BMP Monitoring Report

2010 annual report covering calendar year 2009

Report (PDF 2.21 Mb) Certification Letter Included

2009 report covering calendar year 2008

Report (PDF 1.53 Mb) - Transmittal / Certification Letter (48 kb)

2008 report covering calendar year 2007

Report (PDF 170 kb) - Transmittal / Certification Letter (45 kb)

No report was required in 2007 because the new permit was issued that year.

2006 report covering calendar year 2005

Report (PDF 374 kb) - Transmittal / Certification Letter (61 kb) | Appendix

2005 report covering calendar year 2004

Report (PDF 302 kb) - Transmittal / Certification Letter (68 kb) | Appendix

2004 report covering calendar year 2003

Report (PDF, 206 kb) | Appendix

2003 report covering calendar year 2002

Report (PDF, 304 kb) | Appendix

2002 report covering calendar year 2001

Report (PDF, 146 kb) | Appendix

2001 report covering calendar year 2000

Report (PDF, 147 kb) | Appendix

2000 report covering calendar year 1999

Report (PDF, 139 kb) | Appendix

1999 report covering calendar year 1998

Report (LARGE PDF, 1100 kb) | Appendix

1998 report covering September 1, 1997 to August 31, 1998

Report (PDF, 533 kb) | Appendix

For questions about the stormwater website, please contact Blair Scott, Water Quality Planner, King County Stormwater Services Section.