It’s no surprise that many Chicagoans still recoil at the idea of swimming in the Chicago River, what with its infamous reputation as a dumping ground for toxic industrial waste.
But over the last couple of decades, there has been a noticeable, positive shift in how the public perceives and engages with our local waterways. And it’s because of this shift that the annual Chicago River Swim was able to make its historic return last year.
After decades of ecological restoration and advocacy from organizations like Friends of the Chicago River, Urban Rivers, Shedd Aquarium, and more, our rivers are the cleanest they’ve been in generations.
This evolution would not have been possible without sustained investments in civil engineering and infrastructure, including the Metropolitan Water Reclamation District’s (MWRD) Tunnel and Reservoir Plan (TARP), as well as innovative water quality monitoring technology like H2NOW Chicago’s real-time sensors operating beneath the river’s surface.
H2NOW Chicago functions like a weather app for the Chicago and Calumet Rivers. Run by Current, a Chicago-based nonprofit dedicated to solving pressing water challenges with innovative solutions, H2NOW uses and pilots cutting-edge sensing and analytic technologies to measure water quality parameters and communicate them to the public.
Many people assume Chicago’s rivers are always dirty or always safe, but the reality is that river conditions are always changing.
Heavy rainfall, surface runoff, industrial discharges, and boat traffic can cause river conditions to rapidly shift. And while traditional laboratory testing remains the gold standard for assessing water quality, lab results can take up to 24 hours or more to process.
Instead of waiting a full day for lab results when they can quickly become outdated, H2NOW provides water quality readings every 15 minutes.
Using submerged probes designed by Proteus Instruments alongside machine learning technology, H2NOW estimates levels of fecal coliform bacteria, a key indicator of water quality, and then transmits the results to a publicly accessible webpage.
H2NOW’s historic data offers valuable insights into the health of Chicago’s waterways over time. During the recreation season, H2NOW provides a clear picture of current water conditions.
During the 2025 monitoring season, 98% of H2NOW data assessed water quality as “Good” or “Low Caution,” aligning with IL EPA standards for primary contact (activities like swimming) and secondary contact (activities like kayaking). Read the H2NOW 2025 end of season report.
H2NOW also serves as an open-water testbed for trialing new water technologies, where researchers and startups pilot their tech in real-world conditions. Current has run 8 technology pilots through H2NOW to date. Most recently, Current expanded its partnership with startup Virridy to deploy their Lume sensor for monitoring E. coli across multiple sites in the Chicago and Calumet rivers. Check out Virridy’s beta dashboard.
Every year, thousands of people visit H2NOWChicago.org to check river water conditions before heading out on the river. That impact is one reason H2NOW was recognized as a winner of Fast Company’s 2026 World Changing Ideas Awards.
As a free, accessible, and easy-to-understand platform, H2NOW empowers residents and visitors to make informed decisions about how they engage with our waterways, while building public trust and confidence by showing that Chicago’s waterways are healthier than many people realize.
That progress is worth celebrating, and we’re thrilled to support the Chicago River Swim as it returns on September 20, 2026 for a second year after a nearly century-long hiatus.
The return of the Chicago River Swim is a powerful testament to the tireless work of the many organizations, agencies, researchers, and community partners who have helped restore and better understand Chicago’s waterways.
H2NOW’s real-time data offers a window into the river’s evolution, and we’re proud to help connect Chicagoans with the waterways in their own backyard as more people rediscover the river as a place to experience, explore, and enjoy.
Interested in learning more about H2NOW Chicago, supporting this work, or working with us to trial your innovative water technology? Get in touch!
ABOUT CURRENT
Current is an independent nonprofit water innovation hub, founded in Chicago in 2016, with a mission to grow a circular blue economy, accelerate water innovation, and solve pressing water challenges. Current collaborates with industry, innovators, communities, nonprofits, and governments to advance innovative water technologies and policies that boost our economy while protecting our water resources. In 2024, Current was designated by the U.S. National Science Foundation to lead one of nine Regional Innovation Engines, Great Lakes RENEW (Recovery of Energy, Nutrients, critical Elements, and Water). To date, Current and our partners have delivered on RENEW’s waste-to-wealth mission by collectively raising over $123.2M for regional water innovation and economic development, supporting 19 R&D projects, 40+ pilots, and 400+ startups, training 560 people for blue economy jobs, and engaging 1,650 youth in water STEM programming. Learn more.
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