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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Room 1000, Portland, OR 97204

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Stormwater Permit

The City of Portland and its co-permittee, the Port of Portland, implement stormwater management programs under a permit issued by the Oregon Department of Environmental Quality (DEQ) under the federal Clean Water Act (CWA). 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 is in effect for five years (until January 30, 2016). 

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. 

Non-Stormwater Discharges Evaluation Report May 2006

Control Mechanisms for Non-Stormwater Discharges to the MS4