MAILING ADDRESS: 1120 SW 5th Ave, Room 1000, Portland, OR 97204
When the City of Portland began constructing sewers in the late 19th century, sewer pipes carried stormwater, sewage and industrial waste - all combined in the same pipes - directly to the Willamette River and Columbia Slough without treatment.
Watch the CSO program video for more
Thanks to the CSO control program, the Willamette River and Columbia Slough are cleaner than they've been in generations. Willamette River water today is safer for swimming.
Check the Willamette recreation index for E. coli and temperature information
Portland uses rain gardens, green street planters, and other green infrastructure to keep stormwater out of combined sewers and ensure that the Big Pipes continue controlling overflows now and for generations to come.
Learn about green street planters, ecoroofs and other green infrastructure