Phone: 503-823-7740
Fax: 503-823-6995
1120 SW 5th Ave, Suite 613, Portland, OR 97204
Portland's Municipal Stormwater Permit
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Effective Stormwater Management Protects & Enhances Our Waterways
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BES Monitors the System to Detect & Eliminate Illicit Discharges
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Storm Sewers Meet Our Waterways at Outfalls
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BES Maintains Over 440 Miles of Storm Sewers
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Green Infrastructure Reduces Peak Flows & Treats Stormwater as it's Collected
This page is moving! Please visit our new MS4-TMDL Program page at Portland.gov for current content.
The City of Portland and its co-permittee, the Port of Portland, implement stormwater management programs under an Oregon Department of Environmental Quality (DEQ) permit issued under the federal Clean Water Act. The permit is formally called the Phase I National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Discharge Permit.
It is referred to as the NPDES permit, MS4 permit, or municipal stormwater permit.
DEQ issued the first Portland permit in 1995 and renewed it for a second term in 2004 (with modifications in 2005). DEQ issued the final third-term permit on January 31, 2011. The permit expired on January 30, 2016 and has been administratively extended by the DEQ.
The permit requires each co-permittee to develop and implement a Stormwater Management Plan (SWMP) that describes measures the co-permittee will implement throughout the permit term to control pollutant discharges to the storm sewer system.
TMDL Implementation
Click here for information about the City's TMDL Program that includes key strategies the City uses to address pollutants from nonpoint sources and impaired waterways.
Monitoring Plan
Current Monitoring Plan for Stormwater and Surface Water Sampling by the City of Portland in Compliance with MS4 Permit Requirements
2015 MS4 Permit Renewal Application
2015 application for the renewal of Portland's Phase I NPDES MS4 Permit, which was issued in January 2011.
MS4 Permit
A link to the City of Portland's 2021 Phase I Municipal Separate Storm Sewer (MS4) NPDES Permit.
Stormwater Management Plan
The 2011 SWMP describes best management practices and programs the City implements to comply with the MS4 NPDES Permit and reduce pollutants from the MS4 to waters of the state.
Hydromodification Assessment
November 1, 2014 report to the Oregon Department of Environmental Quality
Annual Compliance Reports
Annual stormwater permit compliance reports
- FY 2020-2021 Permit Year 26 Annual Compliance Report
- FY 2019-2020 Permit Year 25 Annual Compliance Report
- FY 2018-2019 Permit Year 24 Annual Compliance Report
- FY 2017-2018 Permit Year 23 Annual Compliance Report
- FY 2016-2017 Permit Year 22 Annual Compliance Report
- FY 2015-2016 Permit Year 21 Annual Compliance Report
- FY 2014-2015 Permit Year 20 Annual Compliance Report
- FY 2013-2014 Permit Year 19 Annual Compliance Report
- FY 2012-2013 Permit Year 18 Annual Compliance Report
- FY 2011-1012 Permit Year 17 Annual Compliance Report
- FY 2010-2011 Permit Year 16 Annual Compliance Report
- FY 2009-2010 Permit Year 15 Annual Compliance Report
- FY 2008-2009 Permit Year 14 Annual Compliance Report
- FY 2007-2008 Permit Year 13 Annual Compliance Report
- FY 2006-2007 Permit Year 12 Annual Compliance Report
- FY 2005-2006 Permit Year 11 Annual Compliance Report
- FY 2004-2005 Permit Year 10 Annual Compliance Report
- FY 2003-2004 Permit Year 9 Annual Compliance Report
- FY 2002-2003 Permit Year 8 Annual Compliance Report
- FY 2001-2002 Permit Year 7 Annual Compliance Report
- FY 2000-2001 Permit Year 6 Annual Compliance Report
- FY 1999-2000 Permit Year 5 Annual Compliance Report
- FY 1998-1999 Permit Year 4 Annual Compliance Report
- FY 1997-1998 Permit Year 3 Annual Compliance Report
- FY 1996-1997 Permit Year 2 Annual Compliance Report
- FY 1995-1996 Permit Year 1 Annual Compliance Report