Wastewater Collection System

The City owns, operates, and maintains more than 206 miles of wastewater collection pipe ranging in diameter from six inches to 36 inches, more than 5,570 manholes, and 10 pump stations.

Wastewater generated in Lake Oswego is treated either at the City of Portland's Tryon Creek Wastewater Treatment Plant or the Clean Water Service's Durham plant. The Tryon Creek plant provides secondary treatment and discharges effluent to the Willamette River near the mouth of Tryon Creek. The Durham plant provides tertiary treatment and discharges effluent to the Tualatin River. The higher level of treatment at the Durham plant is due to the more stringent water quality standards in the Tualatin River basin. Both plants operate under National Pollutant Discharge Elimination System permits and fully comply with the Federal Clean Water Act.

What does it cost to operate the wastewater system?  Charges on your utility bill reflect pipe replacement, treatment costs, system maintenance, and many other system costs.  Check out the Wastewater Utility Financial Plan and Rate Review to see what rate increases will be needed over the next 10 years to provide safe and reliable wastewater service to Lake Oswego residents.

Lake Oswego staff are fully committed to protecting the environment of Lake Oswego and surrounding areas by providing collection and treatment of wastewater within Lake Oswego.

Select our construction projects link to find out about ongoing construction projects related to the City's sanitary sewer system.

Maintenance Services is responsible for the system's operation and maintenance, as well as rat control, sewer odor complaints, service verification, and response to sewer backups, overflows and missing manhole covers.

Contact Maintenance Services for more information:

Maintenance Services
Wayne Benson E-mail
5705 Jean Road
P.O. Box 369
Lake Oswego, OR 97034
Phone 503.635.0280
Fax 503.697.7411

Or, contact Pat McDougal, Associate Engineer, by e-mail or at 503.635.0273.