The Stormwater Management Manual contains Portland’s local requirements for managing stormwater for all new development, redevelopment, and improvement projects.

The manual helps Portland comply with the federal Clean Water Act and the Safe Drinking Water Act, which require stormwater management for both private property and the public right-of-way. The requirements help protect Portland’s streams and rivers for people, fish and wildlife.

Portland developed its Stormwater Management Manual (SWMM) in 1999 and has revised it several times since then. The public comment period is open now for proposed 2016 revisions, including minor changes to Portland City Code 17.38. Learn more about the changes and the comment process at www.portlandoregon.gov/bes/70389. All comments must be received by 5:00 p.m. on Friday, May 6, 2016.

Portland was one of the first cities to adopt post-construction stormwater management requirements, and one of the first to require green infrastructure in development (also sometimes called low impact development).

Rather than putting all stormwater from new development in a pipe and sending it to the public system and local streams, Portland focuses on managing stormwater on-site with vegetated facilities like ecoroofs, bioswales and stormwater planters that allow water to soak into the ground.