Record July Rainfall Prompts Overflow Action

 As July, 2023 ends, it is safe to say that it has been a very stormy and wet month. In fact, more rain fell in the first week of July than typically falls all month, according WGN News’ weather blog. The average rain fall for the month of July is 3.7 inches, yet “a record-setting rainstorm dumped 9 inches of rain on some parts of the Chicago area” on July 2 alone, reports WBEZ radio, “resulting in more than 1,400 Chicagoans who filed reports of flooded basements to 311, the city’s non-emergency helpline.”

The regional combined sewer system cannot always handle the amount of rain that falls during these intense storms as well the daily load of household and industrial waste. Heavy rainfalls, and rapid snowmelt, can overly strain the sewage system, resulting in the release of untreated wastewater into the Chicago-Calumet River system, and, on occasion, Lake Michigan. According to the Metropolitan Water Reclamation District, the sewer and stormwater agency for Cook County, as little as 0.3 inches of rain, depending on the location and severity, can trigger a combined sewer overflow (CSO) at any number of over 300 outfalls that flow directly into the Chicago-Calumet River system in the combined sewer area.

With the aim of helping to relieve pressure on the sewer system to protect the river system, Friends initiated Overflow Action Days in 2014, and have since collaborated with the Metropolitan Water Reclamation District (MWRD) to expand the program’s public reach. 

Based on the concept of Ozone Action Days, Overflow Action Days alert people before, during, and after rainstorms when we need to minimize the amount of water going down drains to reduce the chance of a combined sewer overflow. In other words, you can personally do something to prevent CSOs by limiting your water usage during heavy rainstorms by delaying doing laundry, taking a shower, and running the dishwasher. On our website, we offer more tips on a range of things a person or a family can do, and where you can sign up for our Overflow Action Alerts.

“Reducing use of fresh water and capturing rain where it falls are essential to reducing pollution in the river,” says Margaret Frisbie, Friends’ executive director. “Every drop of water is precious and must be treated that way. Even better, if we use natural systems, such as rain gardens to capture it, we layer on huge benefits for human and ecological health.”