A plumbing job that became a holiday
Ask most people why the Chicago River turns green every March and you'll hear "the city does it." The city doesn't. Plumbers do. Specifically, members of Chicago Journeymen Plumbers' Local Union 130 have dyed the river every year since 1962, and Local 130 sponsors the downtown St. Patrick's Day Parade that steps off the same day. The plumbers who show up at the river at dawn, and the ones marching and working the parade route, are volunteering their Saturday.
That's the same union whose plumbers Plumbers 911 Chicago dispatches to your basement the rest of the year, which is why we're telling the story.
It started with a leak
The dye came out of real plumbing work. In the early 1960s, plumbers traced illegal sewage discharges into the river by pouring a tracing dye into drains and watching where the color came out. The story in the union hall goes that the business manager at the time, Stephen Bailey, noticed a plumber's white coveralls stained bright green from the stuff and had the idea: if a little dye in a drain shows up in the river, enough dye in the river would turn the whole thing green for the parade.
The first year, in 1962, they used a lot of it, and the river stayed green for about a week. The amount came down year by year until the color lasted roughly the length of the day. In the mid-1960s the formula changed to the one still used now: an orange, vegetable-based powder that's environmentally safe and turns the water green on contact. The exact recipe is a Local 130 secret, which is the one part of the operation the plumbers won't explain.
How it's done
Two boats. The larger one carries the dye and a few members who sift the orange powder into the water from the back; the smaller one follows and churns the wake so the color spreads evenly. They work the stretch of the main branch between Columbus Drive and the State Street area. It takes under an hour, and the green holds for about five hours, which carries it through the parade. Then it fades on its own.
The people doing it are plumbers and their families, several of whom have been part of the crew for generations. Nobody gets paid for it.
The parade
Chicago's downtown St. Patrick's Day Parade runs along Columbus Drive in Grant Park, on the Saturday before March 17 (in 2027, that's Saturday, March 13). Local 130 is the sponsor. Members march, carry the banners, staff the route, and support the floats and the bands. If you see plumbers in the parade, that's who you're looking at: apprentices, journeymen and retirees from the same local, there on their own time.
For a union whose daily work is invisible by design — good plumbing is the stuff you never think about — it's the one day a year the whole city sees them.
Practical notes if you're going
- River dyeing starts around 10 a.m. on parade Saturday. The best views are from the Michigan Avenue and Columbus Drive bridges and the Riverwalk. It fills up early.
- The parade steps off at 12:15 p.m. on Columbus, from Balbo north to Monroe. Dress for the lake wind; mid-March in Grant Park is colder than the forecast says.
- Public transit. Drive downtown that day and you'll regret it. Metra and the CTA run extra service.
- The dye is safe. It's been reviewed for decades and is non-toxic to the river's fish and plants. You still shouldn't swim in the Chicago River in March, for reasons that have nothing to do with the dye.
What tracing dye has to do with your house
The technique that started all this is still used. When a plumber needs to find out where a drain actually goes, whether a floor drain is tied to the sanitary line or the storm line, whether a mystery leak in a basement is coming from the sewer or from groundwater, or whether a downspout is illegally connected, they pour a tracing dye in one end and watch where it shows up. Paired with a camera inspection, it answers questions about old Chicago drain systems that nothing else can. If you've got water appearing somewhere it shouldn't and nobody can explain why, ask for a dye test.
The point
The green river is a reminder that the plumbers in this city have a history and a standard. The ones Plumbers 911 Chicago dispatches went through Local 130's five-year apprenticeship, hold their City of Chicago or State of Illinois license, and show up for the parade on their own time. If you need one the rest of the year, call 833-758-6911. A live person answers around the clock.
Happy St. Patrick's Day from the people who turn the river green.