Environmental Services collects water samples from the river monthly at three locations to analyze long-term water quality trends for nutrients, metals and bacteria. From May to October, field staff also collect weekly samples from five  Willamette River public access points to give recreational users more frequent information about bacteria levels.

1. Waverly Country Club - River Mile 17.9
Samples from this location tested monthly
2. Sellwood Riverfront Park Dock - River Mile 16.4
Samples from this location tested weekly from May to October
3. Willamette Park Boat Launch - River Mile 15.7
Samples from this location tested weekly from May to October
4. Riverplace Marina Boat Dock - River Mile 13.2
Samples from this location tested weekly from May to October
5. Portland Boathouse Dock - River Mile 12.9
Samples from this location tested weekly from May to October
6. Morrison Bridge - River Mile 12.7
Samples from this location tested monthly
7. Railroad Bridge - River Mile 6.8
Samples from this location tested monthly
8. Cathedral Park Boat Launch - River Mile 5.6
Samples from this location tested weekly from May to October