The History of Chicago River Dyeing

If you visit Chicago during St. Patrick’s Day, you will undoubtedly witness one of the strangest traditions in the country: the river dyeing.

For six decades, Chicago has transformed the waterway into a shade of bright emerald green by dumping 100 pounds of environmentally friendly dye right into the Chicago River. This year will mark the 70th anniversary of this unique event. 

According to Chicagoist, in 1961, Stephen Bailey, the business manager for the Chicago Journeymen Plumbers Local Union, noticed that a plumber’s white overalls had bright green stains all over it, seemingly matching the emerald green often associated with Ireland.

The green dye was originally used to help in the effort to clean up the river’s waterfront areas. According to NPR, when Richard J. Daley assumed mayorship of Chicago in 1955, he endeavored to discover where the sewage in the water was originating. The green dye was used to help identify the source of leaky pipes.

Then, in 1962, the Plumbers Local Union decided to use 100 pounds of that dye in the river to turn it green for St. Patrick’s Day – and it stayed that way for a week!

Fun fact: Daley originally wanted to use the green dye to colorize a section of Lake Michigan until he was persuaded to dye the more manageable Chicago River instead. 

To see the river dyeing experience for yourself, adorn your greenest attire and join the city of Chicago this year on Sunday, March 16, for the 2025 Chicago St. Patrick’s Day Parade. The parade is sponsored by the Chicago Plumber Local 130UA and will begin at 12:15 PM.  The river dyeing will begin at 10am.