Information about Portland's combined sewer system and CSO controlRead More…
1120 SW 5th Avenue, Room 1000, Portland, OR 97204
Portland completed combined sewer overflow (CSO) program construction in 2011 to reduce CSOs to the Columbia Slough by more than 99% and to the Willamette River by 94%.
Before CSO control: An average of 50 Willamette River CSO events each year.
Today: An average of four CSO events each winter and one event every third summer.
Lesley Stahl narrates Portland's CSO Program, a video overview of Portland's 20-year program to control combined sewer overflows.
Cornerstone projects - downspout disconnections, sumps, stream diversions and sewer separations - removed millions of gallons of stormwater from combined sewers to allow construction of smaller CSO control facilities.
Big Pipes - one on the Columbia Slough, two on the Willamette River - intercept combined sewage and stormwater and direct it to the treatment plant.
Video overview of Portland's 20-year combined sewer overflow control program
Downspout disconnection, sump installation, stream diversion and sewer separation are cornerstones of CSO control
CSO control tunnels on the Columbia Slough and Willamette River
See if a combined sewer overflow (CSO) or sanitary sewer overflow (SSO) advisory is in effect
Get e. coli and temperature information for the Willamette River in Portland
Green infrastructure and grey infrastucture work together to prevent sewage overflows
Information about Portland's combined sewer system and CSO control