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 - September 18, 2014

How is the new water pipeline being built under the Willamette River?

A drill rig loading drill pipe for the pilot hole, at the construction site just north of Mary S. Young Park, West Linn

Over 10 miles of large diameter water pipeline is currently under construction in Gladstone, West Linn, Lake Oswego and Tigard as part of the Lake Oswego-Tigard Water Partnership project. Construction methods for the pipeline vary between traditional cut-and-cover trenching and trenchless methods including horizontal directional drilling, micro tunneling and pipe ramming. While much of the pipeline is being installed in streets using typical cut-and-cover trenching, a special technique is used to get across the Willamette River.

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Thursday - September 18, 2014

West Linn Pipeline Construction Update

Crews are making the final pass under the river, using a drill bit or reamer to enlarge the hole for the pipe to be pulled through in October.

Drill pipe is attached to the reamer.

Construction updates include all current or upcoming pipeline work for the project in West Linn. Read below for specific information on the following:

  • Horizontal directional drilling under the river, near Mary S. Young Park
  • Highway 43 pipeline construction (night work) - expected to start this fall
  • Neighborhood construction update meetings - first and third Tuesdays of the month

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Friday - September 12, 2014

Water Treatment Plant Construction Update

Milestones reached at the site

A successful milestone was reached this week – it is one year since construction started at the plant. The nine acre site has been transformed to one that continues to have an operating 16 MGD plant, but that plant is now surrounded by the framework for the improved plant.

More than 60% (663) of the total auger cast piles have been installed on site to date. Over 7,000 cubic yards of concrete have been poured for seven new structures on the site. Concrete is complete for the clearwell and solids storage tank. The concrete is almost complete for the gravity thickener, mechanical dewatering and ballasted flocculation structures.

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