Editor's Note: A live view of the Chicago River on Monday, March 17 is streaming in the player above.
The Chicago River getting dyed green is one of the city's most iconic St. Patrick's Day traditions and 2025 was no exception, as thousands lined the Riverwalk to see the river transform to an emerald green.
While many of the celebrations took place over the weekend, the holiday officially falls on Monday. Is the river still green to mark the big day?
According to Choose Chicago, the bright green color was only expected to last for a few hours, though the green hue could remain for days.
As of 8:30 a.m. Monday, March 17, the shamrock color over the river was still as bright as ever, photos and videos showed.
In 2024, the Chicago River remained green for several days after the dyeing, still appearing emerald in the middle of the following week.
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When does Chicago dye the river green for St. Patrick's Day?
Each year the Chicago Plumbers union uses boats along the Chicago River, using a concoction that sprays dye out of plumping pipes and spout pumps.
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But the mysterious mixture doesn't come out green - it's actually orange.
However, once the dye sets in, the color changes to green.
The date changes each year, but occurs either the weekend before or after St. Patrick's Day. For 2025, the Chicago River Dyeing took place on Saturday, March 15.
What's in the dye?
The answer to this has remained a mystery for years.
The plumbers union, Choose Chicago says, "still holds the river-dyeing honors today."
But you won't be able to find their recipe anywhere.
"Their environmentally friendly dye formula remains a closely kept secret," Choose Chicago says.
When did the tradition begin?
The story began in 1961 when Stephen Bailey, the business manager of the Chicago Plumbers Local 130 union, was approached by a plumber whose overalls had been dyed a remarkably brilliant shade of green.
According to the story, the dye used to detect leaks in the sewer system along the Chicago River turned the water green, and the idea was born to dye the river green in honor of St. Patrick’s Day.
Each year, the Journeyman Plumbers Local 130 heads out on boats onto the Chicago River and pours an orange concoction into the water. In a seeming blink of an eye, the dye turns from orange to green, and the water maintains that brilliant hue for the iconic holiday.
