Waluga Reservoirs

New entrance to the reservoir site
Inside the new reservoir
Tigard and Lake Oswego elected officials at the ribbon-cutting
Completed Waluga Reservoir 2 with final landscaping

Facility Overview

(click image to open PDF, 273 kb)


As part of the system upgrade, increased capacity was required to serve Lake Oswego and Tigard communities. A new 3.5 million gallon (MG) reservoir (Waluga Reservoir 2) was constructed next to an existing 4 million gallon reservoir (Waluga Reservoir 1) at the Waluga site on Carman Drive in Lake Oswego.

Waluga Reservoir 1 was built between 1980 and 1982. It is a crucial component of the Partnership’s system to provide drinking water to Tigard and Lake Oswego residents.

The new Waluga Reservoir 2 works in tandem with Waluga Reservoir 1, to store and provide clean drinking water for both communities. Water stored at the site maintains a reliable water supply for Lake Oswego and the reservoirs enable water supply for Tigard via the Bonita Pump Station. The Waluga Reservoir 2’s capacity and elevation improves water pressure to the nearby service area, which previously experienced substandard pressure during peak demand periods.

Waluga Reservoir 2 was designed and built to the latest structural, building, and seismic codes, and to the highest class of standards (IBC Occupancy Category IV) required for essential public facilities such as hospitals, designated emergency shelters, and structures with critical national defense functions. This improves the water system’s reliability by providing additional storage that can withstand significant seismic events.

In late 2015, the newly constructed Waluga Reservoir 2 was placed online, which allowed the existing Waluga Reservoir 1 to be completely drained for some planned improvements. While the reservoir was drained, a thorough structural inspection was conducted of the interior and exterior of the tank. The inspection discovered defects in the tank roof and supporting columns. The walls and floors are in excellent condition, but the roof system required replacement as soon as reasonably possible. In 2016, the Partnership developed and implemented a plan to replace the roof and the supporting columns.


Major construction on the Waluga Reservoir 2 began in spring 2014 and was complete in summer 2015, with final landscaping and site restoration complete in fall 2015. During construction, 10 million pounds of onsite rock was reused as backfill, reducing truck traffic.

A ribbon-cutting and celebration event was held on October 9, 2015 with Partnership and City staff, elected officials, crews and local neighbors.

Construction began to replace the Waluga Reservoir 1’s roof and columns in fall 2016 and was complete in spring 2017.

Planning History

When approached by Partnership representatives about plans to build a new reservoir on City property near the existing WR1, many nearby neighbors expressed concern.

Five well-attended meetings were held with neighbors to discuss how to address concerns ranging from safety, to reservoir visibility, to construction impacts. Through these meetings, a Good Neighbor Plan (pdf, 800 KB) was developed. The plan specified actions and commitments to help ensure the new reservoir and associated pipeline was designed, built, and will be operated in a neighbor-friendly way.

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