This achievement highlights the transformative role the Big Pipe Project has had on Willamette River water quality and how the City's investment in major infrastructure projects can create positive impacts for Portland.
The milestone was also celebrated by a swim hosted by the Human Access Project, an advocacy group formed to promote a safer Willamette River.
About the Big Pipe Project
- Completed on time and on budget in 2011, the Big Pipe Project took 20 years to build and cost $1.4 billion.
- Before the project’s completion, Portland experienced an average of 50 CSOs to the Willamette River annually, sometimes lasting for days.
- Today, CSOs are fewer, shorter, and smaller. Overflows to the Willamette have been reduced by 94% and 99% to the Columbia Slough.
- During rainy periods, the public can track how the Big Pipe Project is actively preventing combined sewer overflows via the Big Pipe Tracker.
Reduced Overflows, Revitalized Recreation
The Big Pipe Project’s impact extends beyond reducing overflows into the Willamette River. With a significant drop in combined sewage came a reduction in E. coli bacteria—a major health concern and long-time barrier for river recreation. Today, the river's water quality is safe for recreation most days throughout the year, and swimming, kayaking, and paddle boarding have now become commonplace.
“Going a year without a combined sewer overflow would not be possible without the Big Pipe Project,” said Environmental Services Director Dawn Uchiyama. “This milestone is a powerful reminder that our investments in infrastructure have lasting and meaningful impacts on our community. Thanks to the Big Pipes, Portlanders' relationship and connection to the Willamette River has been transformed.”
“While the Big Pipe System is impressive in scale, the work that went into designing, constructing, and now operating and maintaining the Big Pipes is equally impressive,” added Priya Dhanapal, Deputy City Administrator for Public Works. “The work that we do and the strategic investments we make help shape the future of our city and are essential to protecting our natural resources for generations to come.”
Continuing to Invest in Portland
The Big Pipe Project is just one part of Portland’s larger sewer and stormwater system that Portlanders depend on every hour of every day. Environmental Services manages, maintains, and operates over 2,000 miles of sewer pipes, nearly 3,000 green street planters, 100 pump stations, and two treatment plants. The Bureau also works to restore hundreds of acres of waterways and natural areas across the city.
Environmental Services continues to make significant infrastructure investments, such as the Secondary Treatment Expansion Program (STEP) at the Columbia Boulevard Wastewater Treatment Plant. This $515 million investment is the largest improvement project at the plant since the 1970s. STEP will increase the plant’s capacity, resilience, and efficiency, ensuring it meets the needs of Portlanders and protects the environment now and into the future.
While this one-year milestone is noteworthy, it is not Portland’s longest streak without a CSO. The city previously achieved a 499-day streak from August 2019 to December 2020. However, Environmental Services’ continued focus on reliability and resiliency ensures milestones like this will remain common, building confidence in the health and future of Portland’s waterways.
About Environmental Services
Environmental Services - the City of Portland’s sewer and stormwater utility - protects public health and the environment by collecting and recovering resources from the city’s wastewater, managing stormwater, and restoring and protecting Portland’s rivers, streams, and watersheds.