Chicago Faces Increased Combined Sewer Overflows Amidst Extreme Weather
Chicago is experiencing an increase in combined sewer overflows into the Chicago River and its tributaries, such as Bubbly Creek, as extreme weather and heavy rainfall events continue to overwhelm the city's wastewater system.
Chicago, IL, September 22, 2026 —
Chicago is currently facing a notable increase in combined sewer overflows (CSOs) that are impacting the Chicago River and its tributaries, including Bubbly Creek. This trend is attributed to the growing frequency and intensity of extreme weather events and heavy rainfall across the region.
The city’s existing wastewater infrastructure, which combines sanitary sewage and stormwater in a single pipe system, is reportedly being overwhelmed by the volume of precipitation. When the system reaches capacity during heavy downpours, untreated or partially treated wastewater is discharged directly into local waterways to prevent backups into homes and streets. These discharges are known as combined sewer overflows.
The Chicago River, a vital artery for the city, along with its connecting waterways like Bubbly Creek, are the primary recipients of these overflows. The sustained impact of these events raises concerns about water quality and the health of aquatic ecosystems within these urban water bodies.
Official figures on the exact number of recent overflow events or the volume of discharged wastewater were not immediately available. The specific contractors involved in managing the wastewater system during these periods were also not detailed. Investigations into the long-term effects of these increased CSOs on the river’s environment are ongoing.
City officials have noted that the escalating challenges posed by extreme weather underscore the strain on urban infrastructure designed decades ago. While the system is engineered to handle certain volumes of stormwater, the current pattern of unpredictable and intense weather is testing its limits more frequently than anticipated.
Story summarized from the original created by Molly DeVore on blockclubchicago.org, see more information here.
