Note on Algae: While Environmental Services tests for bacteria, the Oregon Department of Environmental Quality monitors another potential hazard: algae blooms. These can form in slow-moving parts of rivers and lakes during hot weather.
If you see water that looks green or has a coating on the surface, stay out.
To check for current health advisories, visit the Oregon Health Authority’s Harmful Algae Bloom webpage.
Water Quality Testing Locations
Environmental Services tests the Willamette River for E. coli bacteria and temperature at eight locations along the Willamette River.
- Weekly testing is weather-dependent but generally takes place May through September, with results posted every Friday.
- Monthly testing happens year-round to track long-term trends.
- River Mile 17.9 – Waverly Country Club (Monthly, Year-Round)
- River Mile 16.4 – Sellwood Riverfront Park Dock (Weekly, Summer Only)
- River Mile 15.7 – Willamette Park Boat Launch (Weekly, Summer Only)
- River Mile 13.2 – Riverplace Marina Boat Dock (Weekly, Summer Only)
- River Mile 12.9 – Portland Boathouse Dock (Weekly, Summer Only)
- River Mile 12.7 – Morrison Bridge (Monthly, Year-Round)
- River Mile 6.8 – Railroad Bridge (Monthly, Year-Round)
- River Mile 5.6 – Cathedral Park Boat Launch (Weekly, Summer Only)
Want to receive the weekly water quality results directly to your email inbox? Sign up for the check-the-rec email bulletin and get the results every Friday.
Sign up for the check-the-rec email bulletin
Stay safe on the river
Know the water. Know your limits. Stay safe.
Many factors affect safety when recreating in the Willamette River, not just water quality. Be aware of:
- Cold water temperatures are healthy for fish but can be uncomfortable or even unsafe for people.
- Strong currents and debris, especially after rain or near bridges.
- Your own swimming skills and comfort in open water.
Frequently asked questions
How did the river become clean enough for recreation?
The federal Clean Water Act has led to major water quality improvements across the country. In Portland, those improvements include the $1.4 billion Big Pipe Project.
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, which is a key indicator of fecal matter and the primary health concern for swimming and other direct-contact recreation, according to the Oregon Department of Environmental Quality.
Other E. coli sources include poop from wildlife and pets.
Is it safe to recreate at Portland Harbor?
The Portland Harbor Superfund Site contains contamination that is primarily bound to sediment (mud) at the bottom of the river and in resident fish—species that stay in the area and do not migrate. Contamination levels in the water itself are too low to harm health. Avoid disturbing the riverbed sediment and do not eat resident fish.
Where can I swim?
Portland Parks & Recreation offers suggestions on where to swim and how to stay safe when recreating in the Willamette River.
Does Environmental Services test for algae?
While Environmental Services tests for bacteria, the Oregon Department of Environmental Quality monitors another potential hazard: algae blooms. These can form in slow-moving parts of rivers and lakes during hot weather.
If you see water that looks green or has a coating on the surface, stay out.
To check for current health advisories, visit the Oregon Health Authority’s Harmful Algae Bloom webpage.