How Does Chicago’s River Turn Green every St. Patty’s Day?

Every March 17th since 1962, the Chicago River turns green to celebrate St. Patrick’s Day. In other words, it gets to look like a Willy Wonka candy river that would get Augustus Gloop excited. Normally if your water is green it means you have a problem, but this day is an exception. On March 17th, even the river gets to be Irish for a day.Chicago river green - St Pattys Day image 1

But how does it happen you might ask? The operation is carried out every year by Chicago’s plumber union. A crew of 6 pours dye into the river. The dye is a powder substance that is orange colored until it turns green when it touches the water. Although the exact recipe behind the dye is top-secret, the dye is (surprisingly) environmentally friendly and has been described as similar to food coloring.

The crew works from 2 boats. One large boat holds 4 crew members while a smaller boat holds 2. The larger boat takes point and disperses the dye into the water while the other boat follows behind to spread the dye.

The entire process takes 40 pounds of powder about 45 minutes to turn the water green. How long the color lasts can vary but the water can remain green up to a few days.

If green rivers aren’t your thing and you wish to celebrate St Patty’s day in the motherland, visit the Irish village of Dripsey. The village holds the second shortest St. Patty’s Day parade in the world. The parade lasts for 100 yards, or the distance in between the village’s two pubs. You have to hand it to them, at least the Irish have their priorities straight. If you don’t like parades either, visit the Guinness brewery in Dublin. If you can’t make it this year, don’t worry. Ireland granted the brewery a lease of 9000 years (not a typo) for the land the brewery sits on. Once again, priorities all figured out.

Chicago river green - St Pattys Day image 2

At, we usually celebrate with some Irish soda bread in the break room and greening up the office with some Myers and Zoeller pumps. Not only is St. Patrick’s Day a golden opportunity to justify listening to bagpipe music but it’s also the only socially acceptable day of the year to wear green pants and a hat with a buckle on it.

From all of us here at, stay safe and have a great St. Patrick’s Day!

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