Come on in – the water’s fine!

Despite public perception (which we are trying to change), the Willamette River is approved for summer swimming, except in the now very rare instances when Combined Sewer Overflow (CSO) conditions are present.

With the Big Pipe project now complete, it’s expected that a CSO will occur only once every two summers (but very likely never again). You are more likely to see a whale swim up the Willamette than see a CSO in summer! Oregon DEQ states that when CSO conditions are not present, “the Willamette River is safe for swimming and other recreational uses.”


Questions? Questions? Visit the Oregon Department of Environmental Quality for a water quality overview and visit the City of Portland Bureau of Environmental Services Check the Rec page for water quality monitoring – weekly in the summer at five sites and monthly year-round.


Isn’t the Willamette River kinda gnarly?

The Big Pipe project, completed in November 2011 is the largest public works project in Portland's history.  The work on The Big Pipe was initiated by a lawsuit from Northwest Environmental Advocates under the Federal Clean Water Act.


The Big Pipe cost was $1.44 billion and took 20 years to complete.  The Big Pipe system was put in place specifically to address Combined Sewer Overflows (CSOs) into the river.  The City of Portland Prior to The Big Pipe being complete it only took 0.1" of rain for raw sewage to flow directly into the Willamette River.  Consequently sewage overflows into the Willamette River used to happen between 50-100 times each year.  Since being put on line, The Big Pipe had a big test in March 2011 when Portland experienced the wettest March on record, the result?  Not one CSO the entire month.  This means Portland will likely never see a CSO in the summertime ever again - that is Big news.  The anticipated sewage overflows will effectviely have been reduced from 50-100 each year to under 4 - all of which will likely happen in the non summer months.


The Oregon Department of Environmental Quality states that when CSO conditions are not present, “the Willamette River in Portland is safe for swimming and other recreational uses.”


The Oregon Health Authority states "The levels of chemical contamination in the Willamette River water are too low to be considered harmful to the health of the public, even for sensitive groups like children and pregnant and nursing women." (see linked document above)