Check the Rec: Willamette River Water Quality Testing

Information
A group of kayakers out paddling and enjoying the Willamette River.
Are you planning to swim, boat, or play in the Willamette River? The river’s water quality is generally safe for swimming and other recreation thanks to the Big Pipe Project and other water quality improvements. Check for yourself. We test the river for bacteria counts regularly and post results.
On this page

Sept. 25, 2024 update: The 2024 summer testing season is complete - all results are GOOD. For details, please explore this page. For the rainy season, please follow the Big Pipe Tracker

Weekly summer testing

Environmental Services samples for E. coli bacteria and water temperature at five popular Willamette River locations each week from late May to September. Samples are taken on Wednesdays, and results are posted by Friday—just in time for the weekend. Results are consistently safe. 

All samples taken during the 2022 and 2023 summer testing period showed good water quality, as do all samples so far in 2024.

Check-the-Rec Updates: Sign up for weekly water quality updates directly to your email inbox through our free GovDelivery subscription service. Updates will be sent on Fridays during the summer recreation months.

Monthly testing

Each month, year-round, Environmental Services collects water samples at three locations to track long-term water quality trends.

Photo shows Environmental Services field scientist taking river water samples from the Firehouse Dock with the Willamette River and downtown Portland in the background.
An Environmental Services field scientist collects river water samples as part of the weekly summer water quality testing.

Staying safe on the river

Keep in mind many factors affect your safety on the river. These include water temperature, currents, and debris in the river, as well as your skills and ability in the water. While cold water is healthy for fish, low temperatures can be uncomfortable and even unsafe for people. Know the water, know your abilities, and stay safe while enjoying the river.

Algae blooms

While Environmental Services tests for bacteria (the leading indicator of whether a water body is safe for recreation), the Oregon Department of Environmental Quality has information about another water hazard, algae blooms, which may form in slow-moving portions of rivers and lakes during hot weather. 
 
If you see water that looks green or has a coating, the advice is, "if in doubt, stay out." To check if there is a current advisory, visit the Oregon Healthy Authority's webpage.

Where to swim

Portland Parks & Recreations offers suggestions on where to swim and how to stay safe when recreating in the Willamette River.

How did the river become clean enough to swim and play?

The federal Clean Water Act has led to vast improvements in water quality in rivers throughout the country. In Portland, those improvements include ratepayers’ investment in the $1.4 billion Big Pipe project—the largest public works project in Portland history. Since Environmental Services completed the project in 2011, almost all combined sewer overflows (CSOs) to the Willamette River have been eliminated. With that drop in sewage, comes a drop in E. coli bacteria, an indicator of fecal matter and the single biggest health concern for swimming and other direct-contact recreation, according to the state Department of Environmental Quality. Other E. coli sources include poop from wildlife and pets. (Thank you for picking up after your dog.)

Find out other ways you can help keep our rivers clean and healthy

Is it safe to recreate at Portland Harbor?

The contamination associated with the Portland Harbor Superfund Site is tightly bound to the sediment (mud) at the bottom of the river and in the resident fish (species that do not migrate). Contamination levels in the water are too low to harm health.

For more information, visit the Oregon Health Authority's webpage.