How can Chicagoans adapt to climate-change-induced flash flooding? Record-breaking storms may be a thing of the past. But Chicago’s local water systems are struggling to keep pace

Chicago saw record-breaking storms hit the city last summer. On the West Side, they overwhelmed the city’s rainwater and sewage systems, flooding water into the streets and basements. Some parts of Chicago saw nearly nine inches of rain during one storm.

Chicagoans reported over 12,000 flooded basement cases between June and July last year—more than the previous two years combined. But these storms and the flooding they bring may be here to stay. 

As climate change drives up Chicago temperatures, the local atmosphere can hold more water vapor and humidity. Storms are becoming more frequent and intense with the extra moisture to tap into, according to Daniel Wright, associate professor of water resources engineering at the University of Wisconsin.

“These summertime thunderstorms last a couple of hours and produce high amounts of rainfall,” he said. “Stronger thunderstorms dump a lot of rainfall, and there is nowhere for the water to go aside from our storm sewers.”

Many of Chicago’s sewer systems were built over 100 years ago, combining rainwater runoff in sewage into the same pipes. They were made for less intense rainfall conditions that no longer exist. When heavy rainwater enters the system, they can’t handle overflow, said former Illinois State Climatologist Jim Angel.

“We’ve got aging infrastructure, and we’ve got an urban environment that encourages lots of runoff,” he said. “You’ve got roadways, parking lots, and buildings that don’t allow the water to soak in. Instead, it immediately runs off into the storm sewers and your basement.”

Replacing those pipes with larger ones that can handle Chicago’s flood risk may take decades. Now, scientists are looking toward green infrastructure to capture excess rainfall before it hits the sewers. It mimics how natural landscapes, like forests and meadows, soak up rainfall and gradually release it into water systems.

“We have to find a safe place to store the water,” said William Gonwa, professor of civil engineering at the Milwaukee School of Engineering. “Say you store some water on a rooftop or make semipermeable pavement? You’ll let that excess water be stored in the ground by wetting the soil.”

Chicago is likely to see more intense storms and flooding this summer. Here’s what experts say Chicagoans can do to adapt to those summer showers.

  • Invest in green infrastructure at the household level. By planting rain gardens, homeowners can cut down the amount of water entering the sewer system all at once.
  • Keep any valuables or vital utilities out of basements. Flooding can happen in minutes, so keeping the irreplaceable on the floor above can help.
  • Buy flood insurance. Most home insurance policies do not cover flood damage, but purchasing subsidized insurance through FEMA or the private market is wise.