1120 SW 5th Ave, Suite 613, Portland, OR 97204
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.
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.
Current Monitoring Plan for Stormwater and Surface Water Sampling by the City of Portland in Compliance with MS4 Permit Requirements
2015 application for the renewal of Portland's Phase I NPDES MS4 Permit, which was issued in January 2011.
A link to the City of Portland's 2021 Phase I Municipal Separate Storm Sewer (MS4) NPDES Permit.
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.
November 1, 2014 report to the Oregon Department of Environmental Quality
Annual stormwater permit compliance reports