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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

More Contact Info

Columbia Boulevard Wastewater Treatment Plant Odor Investigations

August 19, 2015

For more information contact Debbie Caselton at 503-823-2831.

Last summer, Environmental Services staff began investigating unusual odors reported around north Portland and near the Columbia Boulevard Wastewater Treatment Plant. After significant effort, the investigation discovered that the source of some odors was industrial solvents, particularly DMSO (dimethyl sulfoxide). DMSO is odorless but degrades in the sewer system and can cause a sickly-sweet chemical odor.

In June, Environmental Services identified Portland companies that were discharging DMSO to the city sewer system and informed them that city code prohibits any discharge that creates noxious odors. The companies immediately ceased DMSO discharges and odor reports diminished.

Odor reports from our neighbors were instrumental in Environmental Services efforts to identify and eliminate these discharges to our system.

To report sewer odors online or to subscribe to receive odor alerts by email, go to or call 503-823-1700.