Lake Oswego Water Treatment Plant

Facility Description

The City of Lake Oswego has operated a drinking water treatment plant in West Linn’s Robinwood neighborhood since 1968. The Lake Oswego Tigard Water Partnership plans to upgrade and expand the treatment plant, located between Kenthorpe Way and Mapleton Drive, to meet current and future drinking water needs. The upgraded plant will supply Lake Oswego and Tigard, and will continue to serve as West Linn’s sole source of emergency and backup water supply.

History of the Water Treatment Plant

Built in 1968, Lake Oswego’s water treatment plant was originally located in unincorporated Clackamas County. The area was later annexed by West Linn. Through its 44-year history the plant has earned a reputation as a good neighbor. The City of West Linn has approved land use applications for upgrades and expansions three times since the plant was built.

It is not uncommon for wastewater and water treatment plants to be located in residential areas. South Fork Water Board’s treatment plant – jointly owned by West Linn and Oregon City – is located in Oregon City’s Park Place neighborhood. Extensive upgrading, expansion and treatment modifications have occurred there over the past several years to serve the two communities.

Water Treatment Plant – Good Neighbor Plan

Lake Oswego Tigard Water Partnership began discussions with the Robinwood Neighborhood Association in early 2010, sharing details of the water treatment plant expansion, listening to suggestions, and finding ways for the upgraded water plant to continue to be a good neighbor. Two years later, the Partnership has met with Robinwood neighbors more than 20 times, developing a Good Neighbor Plan (pdf, 308 kb) that contains the Partnership’s commitments for design–construction–operations of the new facility. Neighborhood input played a big role in design concepts with the addition of numerous plant layout changes and amenities requested by neighbors.


How to Get Involved

  • Click here for upcoming meeting dates.
  • Sign up to receive email notices.  Mark the ‘Water Treatment Plant' as your interest.
  • Click here to contact us by email.
  • Call the Water Hotline (503) 697-6502.

Additional Information

You can find regular updates on the Work Underway page.

Field Updates

Thursday - July 30, 2015

Concrete pours begin for the new WTP filters and administration building

New filters – northwest of site

Crews finished installing the auger cast piles for the pipe encasement and filter slabs. Rebar (pictured right) was installed to support the 54-inch pipe as part of the connection between the new filters and ballasted flocculation, and also for the new administration building. Last week, crews started installing the 54-inch pipe and next week, the new pipe will be encased in concrete. Once this is complete and the concrete forms are removed, crews will backfill the encasement slabs.

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Friday - July 24, 2015

Hwy 43 paving complete, final striping to begin

Crews roll the final mix of asphalt placed on Highway 43 near Laurel Street.

West Linn Pipeline Construction Update - Highway 43 and Mapleton Drive

This update includes information about the following topics. Click below for specific information on each topic:

  • Highway 43 – final paving complete, striping begins next week
  • Mapleton Drive – auger bore complete, sewer relocation mid-August
  • Neighborhood construction meetings - next meeting August 4

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Thursday - July 9, 2015

Trillium Creek tunneling complete

Crews begin grinding a 4-inch deep section of pavement on Hwy. 43 prior to placing new asphalt.

Crews push the last piece of pipe casing through the work pit.

The casing emerges on the other side of Trillium Creek.

West Linn Pipeline Construction Update - Highway 43 and Mapleton Drive

This update includes information about the following topics. Read more for specific information on each topic:

  • West Linn emergency intertie connection – complete and fully operational!
  • Highway 43 – final paving over halfway complete
  • Mapleton Drive – auger bore complete, sewer relocation to begin
  • Neighborhood construction meetings - next meeting July 21

Read More