Heavy spring rain tests a Chicago home’s gutters, sump pump and sewer line all at once. Storms have been busy lately. Illinois State Climatologist Trent Ford told NPR Illinois in August 2026 that this year had been “one of, if not the, busiest years on record for severe weather in Illinois.” This checklist uses guidance from the City of Chicago, the Metropolitan Water Reclamation District (MWRD), the National Weather Service in Chicago, Ready.gov and FEMA.
Why do Chicago basements flood?
Most of the city’s sewer system predates 1930 and is a combined system, meaning storm runoff and household wastewater share the same pipes, WBEZ reports. When heavy rain overwhelms those pipes, pressure can push sewage back into basements. As MWRD senior civil engineer Patrick Jensen told WBEZ, the sewers “simply cannot handle that flow in that fast amount of time.”
The City points to other causes too. Its sewer backup page notes that a high water table slows absorption, that private lines may be blocked or damaged, and that some homes flooded because of ponded runoff entering basement windows and doors. The City installs rain blockers in street catch basins to slow runoff into the sewer, and it is plain about the limits. “Nobody can guarantee you will never flood,” its basement flooding page says.
What should you check outside your home?
Start with where the water goes when it leaves your roof.
- Gutters and downspouts. FEMA advises you to “Routinely clean and maintain gutters, downspouts and splashpads so rainwater flows away from your house” (FEMA).
- Downspout disconnection. The City recommends disconnecting downspouts from the drainage system and sending that water to your lawn, to keep as much water out of the sewer as possible during heavy rain.
- Grading. The EPA says to make sure the ground slopes away from the foundation so water does not enter or collect around it.
- Foundation cracks. FEMA suggests closing cracks with mortar and masonry caulk or hydraulic cement.
- Storm drains. FEMA advises clearing debris from drainage ditches and storm drains. If water sits in your street for long periods, the City says the catch basin may need to be checked for clogs. Call 3-1-1 and ask for the Water Management Leak Desk.
- Rain barrels. FEMA suggests connecting a rain barrel to a downspout. WBEZ notes that MWRD sells discounted rain barrels.
How can you keep sewer water out of your basement?
Several devices can help keep backed-up sewer water from coming up through basement drains. WBEZ describes the first three, and FEMA recommends the fourth.
| Option | What it does | What to know |
|---|---|---|
| Backflow (check) valve | Installed in your private sewer pipe so wastewater flows out and does not back up from the public main | FEMA says to have a licensed plumber install backflow valves for all pipes entering the building |
| Standpipe | Raises the lowest drain opening above the sewer level | WBEZ describes it as a big PVC pipe sealed to the sewer drain in your floor |
| Overhead sewer | Pumps wastewater from basement fixtures up to a pipe near the ceiling or first floor and out of the house | WBEZ calls it a major reconstruction of your internal plumbing system |
| Floor drain plug | Blocks backups through basement floor drains | FEMA recommends drain plugs in all basement floor drains |
Ready.gov’s flood checklist also says to “Install check valves.” WBEZ reports that these solutions tend to be costly, and that some suburbs, including Wheaton, Oak Park and Morton Grove, offer rebates, cost-sharing or grants. Ask a licensed plumber which option fits your home and what permits the work needs.
Is your sump pump ready?
FEMA says “Sump pumps propel groundwater away from your home and can be an excellent defense against basement seepage and flooding.” It also advises, “Choose a battery-operated sump pump in case the power goes out.” Ready.gov makes the same point and suggests you “Consider a sump pump with a battery.” Test your pump before the first heavy rain of the season so you are not finding a problem mid-storm.
Then check your insurance. The Illinois Department of Insurance’s consumer guide says most policies exclude sewer backup and sump pump overflow. It describes a water backup endorsement that pays for damage to a finished basement caused by water that backs up through a sewer or drain or is discharged from a sump pump overflow. Ready.gov adds that homeowners policies do not cover flooding, and that a National Flood Insurance Program policy typically takes up to 30 days to go into effect. Review coverage before storms are in the forecast.
What should you do when heavy rain is forecast?
- Watch for MWRD alerts. When MWRD issues an Overflow Action Alert, it asks residents to delay showers and baths, flush less frequently and wait to run the dishwasher or washing machine. You can sign up to get these alerts by text.
- Move valuables up. Ready.gov says to keep important documents in a waterproof container. Lift boxes and electronics off the basement floor.
- Set up more than one way to get warnings. NWS Chicago says it is important to have multiple ways to receive warnings in case one fails, and that NOAA Weather Radio alerts and wireless emergency alerts save lives.
- Know watch from warning. NWS Chicago explains that a watch means conditions are favorable for severe weather, and a warning means it is happening or about to.
- Pick your shelter spot. NWS Chicago says safe places include storm shelters and basements, and an interior room without windows can also be protective.
How do you stay safe while the storm passes?
NWS Chicago’s rule is “When Thunder Roars, Go Indoors,” and it advises waiting 30 minutes after hearing thunder before going back outside. Indoors, the National Weather Service says to stay off corded phones, avoid touching electrical equipment, avoid plumbing such as showers and dishwashing, and stay away from exterior windows and doors. It also notes that typical surge protectors will not protect equipment from a lightning strike.
On the road, turn around at flooded streets. The National Weather Service says 6 inches of fast-moving flood water can knock over an adult, and 12 inches of rushing water can carry away most cars.
What should you do if water gets in anyway?
- Stay away from wet electrical equipment. Ready.gov says not to touch electrical equipment if it is wet or if you are standing in water.
- Treat floodwater as contaminated. Ready.gov warns that floodwater can be contaminated and contain dangerous debris. Wear heavy work gloves, protective clothing and boots, and keep children out of cleanup work.
- Run generators outdoors only. Ready.gov says to use a generator only outdoors and away from windows.
- Take photos and call your agent. The Illinois Department of Insurance advises photographing damage before cleanup, where it is safe.
- Dry it fast. The EPA says to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth.
Our flooded basement cleanup and sewer backup cleanup pages explain how we handle water in a basement. If wind or a falling tree opens up the roof or a window, see storm damage and board-up.
This article is general information, not legal or insurance advice. Check your own policy and talk with your agent about what your coverage includes.
When to call a restoration company
Call when water is coming into your basement, a sewer line has backed up or a storm has opened up your home. A person answers 24/7. We ask what happened, where the water is and whether the power is on in the affected area. Then we send a crew to remove water, protect the property and start drying. We document everything with photos, moisture readings and notes for your insurance claim. Contact us any time.