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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

MAILING ADDRESS: 1120 SW 5th Ave, Room 1000, Portland, OR 97204

More Contact Info

Tryon Creek Wastewater Treatment Plant

Tryon Creek treatment plantThe City of Portland constructed the Tryon Creek Wastewater Treatment Plant (TCWTP) in 1965 within Lake Oswego city limits next to the Willamette River. The city expanded the plant in 1976 and modified the plant in 2003. The plant treats sewage collected from parts of southwest Portland, unincorporated areas of Multnomah and Clackamas counties, and the City of Lake Oswego.

Tryon Creek is an activated sludge, secondary treatment plant. It’s about one-tenth the size of Portland’s Columbia Boulevard Wastewater Treatment Plant.

The City of Portland Bureau of Environmental Services owns and operates the TCWTP, although the plant treats wastewater from sewer customers of both the City of Portland and the City of Lake Oswego under an inter-city contract.


Environmental Services updated the treatment plant's facilities plan in 2014.


TCWTP Projects on Hold

TCWTP update notice on May 2, 2019

City [Lake Oswego] weighs options for Tryon Creek Wastewater Plant

Lake Oswego Review article on April 12, 2019

City of Lake Oswego: Tryon Creek Wastewater Treatment Plant Project

The City of Lake Oswego is seeking a new and more efficient wastewater treatment plant to replace the existing Tryon Creek Wastewater Treatment Plant (TCWTP) located in Lake Oswego, Oregon.

TCWTP Open House Displays June 6, 2017

Open House re code amendment process

2014 Facilities Plan

Updated facilities plan executive summary

Treatment Plant Photos

Views of the Tryon Creek Wastewater Treatment Plant