Chicago River to Turn Green for St. Patrick's Day

Got story updates? Submit your updates here. ›

The iconic annual tradition of dyeing the Chicago River green to celebrate St. Patrick's Day will take place on Saturday morning. The process, which takes about 45 minutes to an hour, is carried out by members of the Chicago Plumbers Union using a special dye mixture that turns the river a brilliant shade of green. The green color will last for a few hours before slowly fading over time.

Why it matters

Dyeing the Chicago River green is a beloved St. Patrick's Day tradition that has been taking place in the city for decades. It marks the start of a day of festivities, including several St. Patrick's Day parades, that celebrate the city's Irish heritage and culture.

The details

The dye used to turn the river green is a special mixture originally used by plumbers to detect leaks. The plumbers, situated in boats, spray the dye out of plumbing pipes and pumps into the river. The dye starts out orange but quickly changes to a vibrant green once it sets in the water. While the initial brilliant green only lasts for a few hours, the river will retain a shade of green for several days after the initial dyeing.

• The river dyeing process begins at 10 a.m. on Saturday, March 14, 2026.
• The dyeing takes approximately 45 minutes to 1 hour to complete.

What they’re saying

What’s next

The dyeing of the Chicago River marks the start of a day full of St. Patrick's Day celebrations in the city, including several parades.