On St. Patrick’s Day, the Chicago River is dyed green. How is this even possible? Among Chicago traditions like the Thanksgiving Day parade and the Printer’s Row Lit Festival, the beginning of this tradition isn’t necessarily well-known. So, why is the Chicago River dyed green for St. Pat’s? How do they dye the Chicago River green, and how long does the Chicago River stay green? Brush up on your Chicago St. Pat’s trivia with the Skydeck!
How Do They Dye the Chicago River Green?
Back in 1961 city plumbers used a green dye to find leaks in pipes. The story goes that a business manager with the Chicago Journeymen Plumbers Local Union noticed splotches of the emerald green dye on a co-worker’s white overalls. The following St. Patrick’s Day the Chicago River was dyed green for the first time by the Plumber’s Local Union at the request of Mayor Daley, Sr. The union dumped 100 pounds of the dye into the river. These days, the river is dyed with 40 to 60 pounds of an environmentally-friendly dye—they call it “leprechaun dust”— that the plumber’s union has developed over the years. It’s sprayed from a boat and the process takes about two hours, and it happens no matter what the sometimes-blustery March Chicago weather brings.
How Long Does the Chicago River Stay Green?
When those first 100 pounds of green dye were dumped into the Chicago River, the color stayed for a week. Now, with the formula the plumber’s union has developed over the years, the dye only lasts a few hours. It’s just enough time to grab a spot with other celebrants along the downtown river’s edge or on one of the many bridges to catch the annual spectacle before it washes into the Chicago Sanitary and Ship Canal.
How to Celebrate St. Patrick’s Day While the Chicago River is Dyed Green
For 2022 the Chicago River is scheduled to be dyed green by Plumbers Local 130 on Saturday, March 12. The official time hasn’t been announced as of press time, but it’s usually a few hours before the St. Pat’s Parade begins. Before or after you see this one-of-a-kind Chicago spectacle, take in another with the incredible view from the Skydeck! Plan your visit today.