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Chicago River Swim

Sunday, September 21, 2025 Chicago, IL 60601 US

Water Quality Plan

— WE KNOW WHAT YOU'RE THINKING

Swimming in the Chicago River may sound like a wild idea, but the river has come a long way from its industrial past. Today's water quality results suggest that it's not as crazy as it seems.

The Chicago River is cleaner than you think

Through concentrated efforts, the Chicago River is at its cleanest levels on record and the river is primed for swimming. 

For 50 years, advocacy groups like Friends of the Chicago River, Current, and Urban Rivers have worked to clean up and celebrate this unique natural resource. The turnaround has been remarkable and the river is constantly moving toward greater biodiversity. It is now home to countless wildlife including more than 80 species of fish.

The Chicago River is a self-sustaining ecosystem whose health is directly impacted by weather patterns and environmental activity. Water quality readings are typically positive, however there are occasions where conditions are less than ideal. Like any organized open water swim or sanctioned triathlon, the Chicago River Swim will only operate in waters that are deemed safe for human exposure.

Additionally, the river's main channel is fed directly from Lake Michigan. Every time the Chicago Harbor Lock opens, hundreds of thousands of gallons of lake water flow into the Chicago River and head downstream. The event's swim course will be set entirely in the main channel.

Water Testing Process

Analysis for the suitability of Chicago River water for swimmers will come from the advanced qPRC testing protocol through the Department of Environmental and Occupational Health Sciences at the University of Illinois at Chicago. This is the same testing system utilized by the Chicago Park District to analyze water quality on its beaches.

The testing measures for the DNA of microbial pollutants such as e. coli and fecal coliform that could be harmful to anyone with direct contact with the water, including swimmers.

Private testing will begin 19 days prior to the event. Water samples will be collected along the course over nine days leading-up to the event. The last test will be the day prior to the swim, which will support the final Go/No-Go decision for the swim.

Water quality testing thresholds for the Chicago River Swim are noted in the table below (which mirror Chicago Park District beach standards).

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Simply put, the Chicago River Swim is prepared to cancel the swim if the water quality is not consistent with safe direct contact with the water by swimmers.

The Chicago River Swim will continue to monitor conditions and ultimately make decisions while using this data, as well as publicly-accessible data and input from MWRD, the Chicago Department of Public Health and other public safety officials.

 

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