Frequently Asked Questions

What is the status of the the new wastewater treatment facility? 

• In 2024, the project team evaluated competitive procurement delivery methods using public financing for implementing the next phase of the project, which involves completing the designs, constructing the facility, and operating and maintaining the facility under a long-term contract. In May 2024, City Council approved moving forward with a design-build-operate-maintain (DBOM) delivery method.
• In October 2024, the City of Lake Oswego issued a Request for Qualifications (RFQ) to shortlist qualified vendors. In August 2025, the City issued a Request for Proposals (RFP) to provide integrated design, construction, and long-term operations and maintenance services for the new wastewater treatment facility.
• In spring 2026, the City received a formal proposal from Jacobs – a nationally renowned engineering and operations firm – to design, construct, operate and maintain the new wastewater treatment facility.

What are the next steps? 

• Once an agreement is reached and Council approves a proposal, designs will be finalized and land-use permitting will resume.
• Pending contract approval, demolition of the buildings on the new site is expected to take place in 2027, followed by construction.

Who will own the new wastewater treatment facility?

• The current Tryon Creek Wastewater Treatment Plant (TCWTP) is owned by the City of Portland and operated by the Portland Bureau of Environmental Services.
• The current plant services Lake Oswego, parts of southwest Portland, and unincorporated areas of Multnomah and Clackamas counties.
• Lake Oswego contributes more than 50% of sewage to the plant.
• When the project is complete, Lake Oswego will own the new facility. Portland will be a major customer.

When is City Council expected to approve the contract/proposal?

• The project team provided an overview of the technical proposal to City Council at the June 16, 2026 meeting.
• Council is expected to decide on the proposal this fall.

Who will own the new facility?

• The current Tryon Creek Wastewater Treatment Plant (TCWTP) is owned by the City of Portland and operated by the Portland Bureau of Environmental Services.
• The current plant services Lake Oswego, parts of southwest Portland, and unincorporated areas of Multnomah and Clackamas counties.
• Lake Oswego contributes more than 70% of sewage to the plant.
• When the project is complete, the City of Lake Oswego will own the new facility. Portland will be a major customer.

Who will operate the new facility?

As currently planned, the DBOM entity would provide operations, maintenance, repair and replacement services for the new facility.

Schedules are subject to change.

How is the project being financed?

The project is being funded through a combination of federal infrastructure loans (the Water Infrastructure and Innovation Act (WIFIA)), investments from the City of Portland, municipal bonds, System Development Charges (from development), and utility revenue.

Will you need to raise utility rates for Lake Oswego customers?

• Yes, sewer rates fund the sewer system, so a rate increase is needed to finance this essential investment.
• Sewer rates help protect public health, keep our waterways clean, and ensure reliable wastewater service for generations to come.
• Rate increases reflect the costs of safe, reliable systems and the real challenges facing utilities across the country.

How much will the rate increase be, and when will Council be deciding on the planned rate structure?

The project team will be presenting a cost analysis and proposed sewer utility rate structure to Lake Oswego City Council at their September 1, 2026 meeting. Council will vote on the proposal and rate structure at a meeting this fall.

Can grants pay for the project?

Both cities have explored grants through FEMA’s Building Resilient Infrastructure and Communities (BRIC) program as well as through HUD’s Community Project Funding (CPF) program. The project has not been selected for a grant thus far. A Water Infrastructure Finance and Innovation Act loan will help partially fund the project.

The project team will continue to explore opportunities as they arise but grant programs for projects of this scale are rare.

What happens if we don’t replace the plant?

The existing plant is more than 60 years old and is at the end of its useful life. If construction of the new plant is deferred, the maintenance required to keep the existing plant in working order will become more expensive. Then, when the new plant is eventually constructed, it will cost even more. We need to invest now so we have safe, reliable sewer service for generations to come.

What is WIFIA?

• The Water Infrastructure Finance and Innovation Act (WIFIA) program was created by Congress in 2014 to accelerate investment in water infrastructure projects like the Lake Oswego Wastewater Treatment Facility Project.
• The federal credit program helps make critical water infrastructure projects more affordable for communities and their ratepayers. It couples low interest rates with flexible, long-term repayment schedules. This lowers the cost of investment in critical water projects, extending payments over the life of the asset.
• Regionally, the Portland Water Bureau, Willamette Water Supply Program, Cascade Groundwater Alliance, and City of Beaverton have all received WIFIA loans, which will save their ratepayers millions of dollars. Other water and wastewater systems in the region are also applying for these loans to take advantage of the savings from the program.

Does the City have a WIFIA loan?

Yes, on September 9, 2025, the City of Lake Oswego closed a $123 million loan from the US Environmental Protection Agency for the project through the WIFIA program.

EPA’s announcement shared: “This project will help the city modernize its wastewater infrastructure by constructing a new wastewater treatment facility to replace its existing 60-year-old plant. The new facility will be compliant with current structural code, mitigating impacts from seismic activity. Overall, this project improves the city’s wastewater services and reduces the risk of untreated wastewater spilling into the Willamette River.”

Why do we still need to raise rates when we have a WIFIA loan?

The WIFIA loan, combined with the municipal bonds, provides the capital needed to pay for the construction of the plant. While these loans help slow down the rate at which the City has to pay for construction, the existing rates are insufficient to make the loan payments.

Where can I get more information about the WIFIA program?

• WIFIA Program Factsheet
• WIFIA Program Benefits
• WIFIA Website

How can I learn more about the project and rate increases?

In September 2026, the project team plans to hold two virtual community information sessions to provide a project update and discuss the proposed rate increases with the public. More information will be shared once those dates are known.

What kind of treatment technology will be used for the new facility?

The new facility will use a conventional activated sludge process. This approach for wastewater treatment has been used for over a hundred years around the world. This process uses a recycled mixture of oxygen-rich wastewater and concentrated, living microorganisms to rapidly break down organic pollutants followed by gravity settling to produce clean, treated water as the output.

What are the main benefits to this technology?

The major benefit of this technology is that it is proven and reliable method of treating wastewater to a high quality.

How will the new facility elevate the cities’ environmental commitment?

The plant is inherently sustainable by design. The conventional activated sludge process is relatively energy efficient compared to many other treatment options and the level of water treatment provided ensures clean water is discharged to the Willamette River.

Further sustainability measures are not included currently to keep costs as low as possible. However, expansion of these types of features (such as water reuse) has been considered in the design such that they can be efficiently added in the future if desired and as funding allows.

How will the new facility address regulatory requirements?

The new facility will meet more stringent treatment standards than the existing TCWTP, producing effluent (liquid wastewater) that exceeds current treatment requirements for discharge to the Willamette River.

What reliability standard will the facility be designed to meet?

The new wastewater treatment facility will be designed to meet the highest level of reliability (Class IV) as required by Oregon DEQ for wastewater treatment facilities within the Willamette Valley.

How will the new facility improve resiliency?

The new facility will be designed and constructed to meet or exceed the applicable floodplain and seismic (earthquakes) requirements.

Where will the new proposed facility be located?

The proposed site for the new facility is located on the far northwest corner of the Foothills District. A map can be found here.

Are you still acquiring properties for the new facility?

• Yes, the plan is to build a new facility next to the existing plant.
• Lake Oswego has been in the process of acquiring the properties and relocating the impacted businesses since 2021.
• The site serves a critical community need to supply reliable wastewater services to Lake Oswego and Portland.

Why was this location selected as the preferred site? Were other locations explored for siting the new plant?

• The site was selected because it is large enough, safer from flooding, and is close to the existing pipes and outfall to the river (thus not requiring re-routing or building new sewer mains to the plant).
• The new facility needs 6 acres of space and must be close to the existing Treatment Plant because of the utility infrastructure that is required.  As a result, the only option that meets these needs is to acquire the three properties that are next to the existing plant.

Why can’t the new plant be built on the current site?

Consideration was given to building the new facility on the existing Tryon Creek site, however the existing plant needs to be fully operational while the new plant is being built.

What will happen with the property where the existing treatment plant is located?

• The City of Portland currently owns the existing site of the Tryon Creek Wastewater Treatment Plant, which is located within Lake Oswego.  Under the proposed new arrangement, the site will be sold to the City of Lake Oswego.  Once the new facility is complete, the old facility will be decommissioned, demolished, and the land remediated.
• Planning for the future of the Foothills District is a separate project from the new wastewater treatment facility.

How will the proposed new facility benefit the surrounding Foothills neighborhood?

The proposed new wastewater treatment facility will be significantly more neighbor friendly. Benefits for the neighborhood include:

• Smaller footprint – 6-acre footprint compared to 12 acres to expand the old facility
• Better neighborhood appeal – design and landscaping will fit into the Foothills neighborhood
• Reduced odor and emissions
• Earthquake and flood resilient