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

Friday - June 26, 2015

Hwy 43 night paving starts June 28 in West Linn!

Crews begin boring the pipe casing under Trillium Creek.

Horizontal directional drilling site at the end of Mapleton Drive.

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:

  • Safety reminder – drive slowly and obey flagger directions
  • Highway 43 – final paving starts this Sunday!
  • Mapleton Drive – auger bore progressing well
  • Neighborhood construction meetings - next meeting July 7

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Thursday - June 18, 2015

Auger cast pile drilling begins for new WTP filters

Preparing the subgrade

New filters – northwest of site

The new filters are being constructed where the sedimentation basins were previously located.

Excavation is compete for the new filters, and this week crews started installing the auger cast piles for the foundation. More than 160 piles will be installed for the filters. This work will continue over the next two weeks.

During this time, the large vibratory compactor will be used intermittently to help backfill and prepare the subgrade for the next stage of pouring concrete slabs. The compactor has been used throughout construction in other areas across the site. Although the compactor will be located low in the excavated hole, neighbors close to the site should expect an increase in vibration during this activity. 

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Wednesday - June 10, 2015

Pipeline activities underway on Mapleton Drive

This update includes information about the following topics:

  • Safety reminder – drive slowly and obey flagger directions
  • Highway 43 – final paving set to begin in July
  • Mapleton Drive – pipeline activities underway
  • Helpful guidelines - for Mapleton Drive pipeline construction
  • Neighborhood construction meetings - next meeting June 16

For the most up to date information on construction, follow @LOTwater on Twitter, visit work underway, or contact us.

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