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InfrastructureWater Quality

Construction underway on the Georgetown Wet Weather Treatment Station Project

By March 2, 2018September 21st, 2020No Comments

Construction on a water quality project that will help spur the creation of family-wage jobs, preserve neighborhood character, and keep overflows of stormwater mixed with small amounts of sewage out of the Duwamish River during severe rain storms is officially underway.

King County Executive Dow Constantine joined the community to break ground on the Georgetown Wet Weather Treatment Station, a $262 million facility that will treat up to 70 million gallons of polluted runoff a day that currently overflows untreated into the Duwamish River during severe rainstorms.

The new facility is among the final projects that will complete our four-decade effort to control combined sewer overflows, or CSOs, that still occur in older parts of Seattle where rainwater fills up sewer lines originally installed in the early to mid-20th century.

“When people in the South Park and Georgetown neighborhoods told us they wanted King County to make water quality in the Duwamish River a top priority, we listened,” said WTD Director Mark Isaacson.

“We expedited the project schedule and put it first on the list. And we also committed to making sure community values were represented in decisions on facility design, public art and project construction.”

Recognizing the importance of the work, the U.S. Environmental Protection Agency recently selected the Georgetown Wet Weather Treatment Station as one of a dozen projects nationwide that qualify for a low-interest loan through the highly competitive Water Infrastructure Finance and Innovation Act Program.

The project is eligible for $134 million in loan funding, which would finance nearly half of the overall $262 million investment and potentially save sewer ratepayers up to $34 million.


From left to right: Dept. of Natural Resources & Parks Director Christie True; EPA Region 10 Administrator Chris Hladick; Lylianna Allala from the office of U.S. Congresswoman Pramila Jayapal; King County Executive Dow Constantine; Georgetown Design Advisory Group member Victoria Hardy

Community Values – Environment, Education & Jobs

The community played a vital role in the design process. Starting in early 2015, we convened a Design Advisory Group to create guidelines and review design concepts. Over 100 other community members contributed ideas at meetings, events, and through online comments.

Beyond addressing a persistent source of water pollution, the facility also reflects neighborhood values around sustainable design. Features will include a green roof and cisterns to filter and collect stormwater, plus the addition of new trees to improve air quality, a primary concern in an area with one of the city’s highest asthma rates.


When the station is completed, people will see colored piping mapping out the water’s path. Special lights on the building will illuminate when the station is operating, and educational signage will be posted in public areas. There will even be space for environmental learning and school groups.

But the public doesn’t need to wait until the facility is completed to experience art and education. During construction, security fencing will be draped with banners featuring water-themed artwork designed by students at the nearby Maple Elementary school as part of their studies on stormwater and water pollution.

Community members also cited jobs and economic opportunity as an important value.

We responded by putting the project under a Community Workforce Agreement that includes a Priority Hire program, requiring contractors to hire construction workers and apprentices living in ZIP codes with high levels of poverty and unemployment. Not only does the Priority Hire offer opportunity for family-wage jobs on the project, the skills gained are transferrable, which paves the way for careers in the building trades.

Sustainable Engineering

Though the station will rely on traditional “gray” infrastructure to accomplish treat stormwater and sewage, sustainability remains in the spotlight.

Many people are familiar with LEED standards for green building. Now there are similar standards for civil engineering projects using a framework called Envision, and we’re excited that the Georgetown Wet Weather Treatment Station will use that
rating system to create an environmentally responsible project that considers quality of life, conscientious use of resources, and respect for the natural world, including mitigating the impacts of climate change.

Our intention is to achieve the Envision Platinum standard, representing a commitment to the highest level of sustainability across the triple bottom line of environment, economy, and equity.

1406_3841m_CSO-9 WetWeatherTreatment

Overview of how it will work


Runoff from these areas will be treated at the new station

Many Hands

Of course it takes many hands to build these projects. In addition to our incredible internal team of construction managers, project managers, planners and community engagement specialists, the project also enlisted the skills of engineering firm CH2M for technical design and EnviroIssues to assist with public outreach.

On the construction side, Titan Earthwork led the site preparation, and Flatiron West will act as prime contractor. Outfall construction work will be done by Pacific Pile & Marine. The conveyance contract is scheduled for advertisement in late March.

Construction is scheduled for completion in 2022. More detailed information about the project, including updates, is available online.