Cooper Mountain Reservoir Now Under Construction

The city is constructing a drinking water storage reservoir and other associated improvements in the South Cooper Mountain area. This project will provide a seismically resilient backbone storage system that serves to meet the drinking water storage needs of the existing development on the eastern slope of Cooper Mountain, the rapidly growing South Cooper Mountain area, and potentially, the future development, that was recently added to the urban area. The project is located on a city-owned 10-acre property on 18250 SW Kemmer Rd. in Beaverton. This property is also the home of an existing city owned 5.5-million-gallon reservoir. 

This project also includes a drinking water transmission main along Southwest Kemmer Road and other on-site improvements such as a booster pump station building, aquifer storage, a recovery well, a mechanical building and a storage building. The reservoir and other associated components are designed to blend with the neighboring residential community. 

On-site construction started in May 2020 and is scheduled to be completed in late summer 2022. Construction of the 24-inch drinking water transmission main on Southwest Kemmer Road began in January, and as of press time is expected to be completed by late February or early March. During construction, temporary closures are to be expected at/ near 18250 SW Kemmer Rd. 

For more information on the Cooper Mountain Reservoir please contact Project Manager Priya Dhanapal at or visit