Skip to main content
Start of main content

IMCO- Stantec Design/Build Team Assisting Lewiston to Replace a 100-year-old Water Treatment Plant

Innovative plan keeps water flowing while existing facility is demolished; new membrane treatment plant to open in 2023


The City of Lewiston, Idaho, has selected the IMCO - Stantec design/build team to help deliver a water treatment plant retrofit to the community. The project aims to replace the existing 100-year-old plant, which is in need of maintenance, and is at risk of failure from a natural disaster or process equipment breakdown. The treatment plant retrofit will provide the community with clean, reliable drinking water for the next 20 to 40 years.

Stantec—a global engineering, architecture, and design firm—is leading the design of the new plant, which will be built on the existing site because additional land is not readily available. The new membrane treatment plant will have the flexibility to deliver up to 10 million gallons per day (MGD), with space to expand to 16.7 MGD in the future. IMCO Construction is the design-builder overseeing the project from preconstruction through completion. Construction is expected to start in Fall 2021 with the project’s anticipated completion in Spring 2023.

The $27.5 million project requires an innovative approach to provide water to the community of 32,000 throughout the construction process. The existing plant will be largely demolished, and water will be provided via a combination of surface wells and mobile water treatment trailers. The mobile system will augment the wells to meet peak demands during the summer irrigation season.

“We’re excited to help the City of Lewiston upgrade its water treatment infrastructure to provide essential service as the community plans for its future,” said Michael Fuss, Stantec senior principal and Inland Northwest water leader based in Boise, Idaho. “This project is a clear example of the benefits of progressive design/build. Our team of engineers, working with the contractor and vendor, identified the critical risks and time elements and provided the right solution. It’s going to take ingenuity and collaboration to continue providing safe drinking water during construction while helping to deliver a new water treatment plant. Our team is up to the task.”

The project was made possible by the successful City of Lewiston Revenue Bond Election in May 2019. The Lewiston City Council approved the Water System Facility Plan, which recommended upgrading or replacing the 1924-built Lewiston Water Treatment Plant. The City Council subsequently decided to use a progressive design/build delivery approach for the project to get early interaction between design engineers and contractors.

IMCO Construction is a dynamic leader in infrastructure construction, performing complex projects, striving for excellence, and forging strong relationships along the way. IMCO Construction serves industrial and public clients throughout Washington, Montana, Idaho, and beyond. For more information, visit

Stantec is a global leader in the water industry as ranked by Engineering News-Record. The firm’s experience includes more than 1,000 water treatment plants, from some of the most complex facilities in the world to those supporting small, remote communities. To learn more, visit

About IMCO
At IMCO, we take pride in our mission; we proudly build complex projects with integrity, excellence, and safety. Specializing in industrial, hydro, transportation, water and wastewater projects, IMCO Construction provides alternative procurement, design-build, GC/CM, and extensive preconstruction services through innovative and collaborative problem solving. Complex logistics and high-risk environments necessitate a depth of technical construction experience, which IMCO’s team brings to every challenge in order to provide efficient and effective solutions.

About Stantec
Communities are fundamental. Whether around the corner or across the globe, they provide a foundation, a sense of place and of belonging. That’s why at Stantec, we always design with community in mind.

We care about the communities we serve—because they’re our communities too. We’re designers, engineers, scientists, and project managers, innovating together at the intersection of community, creativity, and client relationships. Balancing these priorities results in projects that advance the quality of life in communities across the globe. Stantec trades on the TSX and the NYSE under the symbol STN.

Media Contact                                               

Ashley Kimberley
IMCO Construction
Ph: (360) 671-3936

Ryan Lamont
Stantec Media Relations           
Ph: (213) 955-3528

End of main content
To top