Sewer maintenance crews from Portland, responding Sunday to an odor report on the 6100 block of Southwest Canby Street, found that sewage was spilling into Woods Creek, a tributary of Fanno Creek in Southwest Portland.
Crews from the Bureau of Environmental Services estimate that about 27,000 gallons were released before they stopped the flow by diverting it to a nearby sewer line. Crews posted warning signs along Wood Creek and nearby Fanno Creek, between the Garden Home and Multnomah Village neighborhoods.
City crews continue to investigate and repair the sewer line.
As a precaution, the public is advised to avoid contact with Woods Creek and Fanno Creek in that area for at least 48 hours because of the possibility of increased bacteria in the water.
Bureau officials said the sewage overflow is not related to the City of Portland's combined sewer overflow control system, which protects water quality in the Willamette River and Columbia Slough.