When is the Chicago River dyed green?
The Chicago River has been dyed green on St. Patrick's Day, March 17 every year since 1962. This is undertaken by the Chicago Plumbers Union, and it has been since Chicago Plumbers Union business manager Stephen Bailey came up with the idea over 50 years ago. The dyeing will commence at 9am this Saturday, and tourist boats for the event will start loading at 8am. The river will stay dyed for 24 to 48 hours.
How does Chicago dye the river green?
The Plumbers Union pours a bunch of what's effectively food coloring into the river. It's a powder with a secret recipe that was originally developed to trace leaks in buildings. The crew sets out in at least two motorboats -- an 18-foot boat that dyes the river and a 12-foot boat that churns up the water by chasing the longer boat. It takes around 45 minutes for the dye to take effect.
How many gallons of green dye are put into the Chicago River?
To die the river green, the Plumbers Union pours around 40 pounds of powdered dye, which is orange until it mixes, into the water. The crew used 100 pounds back in 1962 and the river stayed dyed for a week. The recipe was then brought down to 25 pounds because there's such a thing as being too festive, and then finally adjusted to the current measurement as the recipe was refined. But again, it's top secret (they say it's environmentally safe) so we may never know exactly what's in there.
How much of the river will be dyed this year?
This year the dyeing will be extended by a full city block to State Street, which means hundreds more people watching from the four bridges with a view of the river. This means that a third boat will be added to release more dye into the river. In years past the river was only green from Columbus Drive to Wabash Avenue.