Since the completion of the Big Pipe Project at the end of 2011, direct sampling of river water for bacteria during summer months consistently has shown levels well within state guidelines, meaning the river water is safe for direct contact through swimming and other recreation.

Here you can find complete E. coli and temperature test results for the most recent summer season: 2018.

The red line in the charts below show the Oregon Water Quality Standard for E. Coli levels. Above the line means the water is considered unsafe for swimming.

The blue line shows Environmental Services sampling results.

During the 2018 season, all but two samples showed bacteria counts at low (healthy) levels in Portland. 

For those two incidents, Environmental Services took additional samples at those locations, all of which came back at low levels. What that means: While the river is free of sewage overflows and generally free of harmful levels of bacteria, there still can be pockets of exposure to bacteria from people (illicit discharges from boats), pets (please pick up after your dog) or wildlife. A general rule of river safety: be aware of your surroundings, and when playing in the river, avoid swallowing river water.