2020 Stormwater Management Manual Now in Effect

The City of Portland 2020 Stormwater Management Manual (SWMM) became effective Dec. 14, 2020. Until April 6, 2021, project designers can use either the 2016 SWMM or the 2020 SWMM. Starting April 7, 2021, all projects must meet 2020 SWMM requirements.

Please note:

• Land use reviews will be conducted under the manual in place at the time of submittal of a complete application.
• Building permits will be reviewed based on the permit “in date.”
• Public Works Projects will be reviewed based on the date the Concept Development Submittal is accepted for review.
• Capital Improvement Projects and Interagency Projects will be reviewed based on 60% plan submittal date.

The Stormwater Management Manual (SWMM) provides policy and design requirements for stormwater management throughout the City of Portland. The requirements in the manual apply to all development, redevelopment, and improvement projects within the City of Portland on private and public property and in the public right-of-way. Environmental Services revises the Stormwater Management Manual to meet current regulatory requirements and to provide current technical standards.

The City of Portland adopted the revised 2016 SWMM and it became effective on August 19, 2016. As of November 21, 2016, project designers must use the 2016 SWMM.

The City of Portland adopted a Source Control Manual (previously Chapter 4 of the 2014 SWMM) and it became effective on August 19, 2016. As of November 21, 2016, project designers must use the 2016 Source Control Manual, if applicable.