Georgetown Wet Weather Treatment Station

Seattle, WA


Theater of a Storm

Georgetown Wet Weather Treatment Station (GWWTS) will work to improve the ecological health of Puget Sound. During heavy rainfall, combined sewer overflows (CSO) periodically discharge a mixture of sewage and rainwater into water bodies to protect the wastewater treatment system. Georgetown Wet Weather Treatment Station will process combined sewer overflow (CSO) events prior to discharge, effectively treating up to 70 million gallons of combined stormwater and wastewater per day.

GWWTS expands beyond its physical presence, serving as a mechanical substitute for the former ecological filtration of mudflats that historically occupied the lower Duwamish Valley. Where mudflats formerly slowed and cleansed rainwater and tides, GWWTS buffers and treats concentrated stormwater volumes that are the result of urban density and industrial hardscape. It is an industrial ecological machine.

Located at the western gateway to the Georgetown neighborhood in Seattle, GWWTS presents an opportunity to contribute to the edge and gateway conditions of the neighborhood through design and programming opportunities. Community desires include a visual access into the water treatment process, a clear design diagram, public tours, and a collaborative community gathering space. A training room and visible green stormwater infrastructure will serve as a demonstration for future construction in the Duwamish Valley.

The design approach builds upon the durable material opportunities of industrial facilities, using proportion, composition, and massing of steel and concrete forms in an elegant gesture that bridges the industrial and artisanal characteristics of the neighborhood. Integrated architectural lighting embraces the drama that is happening underground, providing a theatrical showcase of the processing features during operation. On the rainiest, coldest days in Seattle, the facility will be luminous and working toward the health of the Duwamish River and Puget Sound.

“Signal is very skilled at working with a diverse community to develop elegant and thoughtful design solutions that engages the public and has excellent functionality. They were up for the challenge of collaborating with highly talented engineers, artists and landscape architects to bring the vision to life.”


Year of Completion: 2022

Gallons per day: 70M

Height at Grade: 100'-/56+

Signal was a team player on this project…and they pushed the design of major industrial facility to higher levels, from inception to completion.

Michael Popiwny, Senior Capital Project Manager, King County Wastewater Treatment Division

Seattle Daily Journal of Commerce
December 19, 2019