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 - August 21, 2015

Mapleton Drive pipeline construction underway

Crews installed pipeline under the railroad tracks on State Street.

Crews install steel plates to support the pipe trench on Mapleton Drive.

West Linn Pipeline Construction Update

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

  • State Street, Lake Oswego – railroad crossing complete
  • Highway 43 in West Linn – all major work complete, pipeline is in service!
  • Mapleton Drive – pipeline construction underway
  • Neighborhood construction meetings - next meeting Sep. 1 at 7:30 a.m.

Read More

Friday - August 14, 2015

Next stage of excavation to begin at the WTP

Concrete pours for the filter slabs (background) and 54-inch pipe for the new filters ready to be encased (foreground)

Water Treatment Plant Construction Update

Information about onsite work over the next few weeks includes:

Truck traffic route change

Please note: starting next week and continuing through the end of major open-cut pipeline work on Mapleton Drive, the WTP contractor will be using Kenthorpe Way to enter and exit the site. Neighbors on Kenthorpe should expect an increase in truck traffic during this time.

Read More

Thursday - August 6, 2015

Mapleton Drive pipeline construction begins week of Aug. 17

Railroad crossing on State Street in Lake Oswego near Foothills Road.

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:

  • State Street Construction – 48-hour weekend construction begins Aug. 15
  • Highway 43 – striping underway
  • Mapleton Drive – major pipeline construction expected to begin week of Aug. 17
  • Neighborhood construction meetings - next meeting Aug. 18 at 6 p.m.

Read More