After a big storm, two Chicago basements on the same block can hold the same few inches of water and end up with very different insurance outcomes. The difference usually comes down to how the water got in. Here is how to tell a sewer backup from a flood, and which coverage usually responds to each.
Before you go look, keep safety first. If water could be touching outlets, cords or appliances and the power may be on, stay out of it. The CDC says to shut off the main power only from a dry location, and to call an electrician if you would have to step into water to reach it. Your electric utility can also help. Call 911 for any emergency.
How can I tell a sewer backup from a flood?
Start with where the water came in. The MWRD says sewer backups usually come from floor drains and plumbing fixtures in basements, while seepage is usually clear water coming through cracks in walls and floors. Its flood resource guide describes overland flooding as heavy rain pushing water in through doors or windows.
Insurance uses its own definition of a flood. FloodSmart, the National Flood Insurance Program’s site, describes a flood as an excess of water on land that is normally dry, affecting two or more acres of land or two or more properties.
| Clue | Sewer backup | Flood |
|---|---|---|
| Where the water enters | Floor drains, toilets, showers and other basement fixtures | Doors, windows and window wells |
| How to report it in Chicago | A 311 Water in Basement request | Call 311 and say it came in through a window or door |
| Standard homeowners policy alone | Usually not covered | Not covered |
| Coverage that usually responds | A water backup endorsement | A separate flood insurance policy |
The City’s Water in Basement request asks whether the water is clean or dirty, where it came from and how deep it is, and the City says not to use that request for water that came in through windows.
Why do Chicago basements get both?
Most of Chicago’s sewer system was built before 1930 and carries rainwater and wastewater in the same pipes. WBEZ reported that, based on MWRD modeling, it can be overwhelmed after two-thirds of an inch of rain in an hour. The City of Chicago says some storms now bring two inches or more in an hour to a single neighborhood, and when the sewer mains fill, water pushes into basements through private sewer drains.
Flood maps do not capture much of this. WBEZ reported in 2023 that less than 1% of Chicago properties are in FEMA’s high-risk flood zone, while the First Street Foundation estimated about 79,000 Chicago properties face high flood risk. The same report found just over 1,000 Chicago homes had a federal flood policy as of June 30, 2023.
What pays for a sewer backup?
Usually a water backup endorsement, which is an add-on to your homeowners policy. The Illinois Department of Insurance says a typical homeowners policy usually does not cover sewer backup, and describes an optional Water Backup and Sump Pump Overflow Endorsement that pays for damage to your finished basement caused by water or waterborne material.
NerdWallet reports that water backup limits often start around $5,000 per year, that quotes it gathered ranged up to the full replacement cost of the house, and that the coverage can cost up to $250 per year. It also notes that water backup coverage does not pay for flood damage.
Illinois now requires insurers to bring this up. Under House Bill 5357, effective January 1, 2025, insurers must give homeowners applicants information about sewer backup and sump pump overflow coverage, including limits and costs, and must send current policyholders that information at least 30 days before each renewal. Sewage cleanup is its own kind of job, and our sewer backup cleanup page explains what it involves.
What pays for a flood?
A separate flood insurance policy. FEMA’s flood insurance fact sheet says most homeowners and renters policies do not cover flood damage, that there is typically a 30-day waiting period before a new policy takes effect, and that over 40% of flood insurance claims come from outside high-risk flood areas.
Through the National Flood Insurance Program, FEMA says a policy can cover up to $250,000 for a residential building and up to $100,000 for belongings. FloodSmart adds that sewer backup damage is covered when the backup is a direct result of flooding, and that personal property kept in basements is not covered.
What does flood insurance cover in a basement?
Less than most people expect. According to FEMA, items need to be connected to a power source or installed in their working location where that applies.
| Usually covered in a basement | Not covered in a basement |
|---|---|
| Furnaces, water heaters and central air conditioners | Finished flooring and finished walls |
| Sump pumps, fuel tanks and well pumps | Bathroom fixtures and other built-ins |
| Electrical outlets, switches and breaker boxes | Couches, computers, televisions and similar belongings |
| Unfinished, untaped drywall, stairways and foundation elements | Dehumidifiers that are not part of the heating and cooling system |
| Cleanup, including pumping out trapped floodwater | Removing items that are not covered |
| Washers, dryers and freezers, only with contents coverage | Items not specifically listed in the policy |
If your basement took on floodwater, our flooded basement cleanup page covers the drying and removal side.
What should I do if I am not sure which one happened?
Document it and let the adjusters sort out the cause. A few steps help either way:
- Photograph the entry point. Get the floor drain, the window well or the door, plus the water line on the walls. FEMA’s claims checklist recommends photos of floodwater lines inside and out.
- Report it to 311 with the source and the depth.
- Tell each insurer what you saw. If you carry both a water backup endorsement and a flood policy, report the loss to both.
- Keep samples of carpet and flooring if you have to throw them out, and keep a log of every call.
- Watch the deadlines. FEMA’s checklist says an adjuster should reach out within 48 hours, and that flood claim documentation is generally due within 60 days of the flood unless your insurer gives you a different timeframe.
This is general information, not legal or insurance advice. Check your own policy and talk to your agent or adjuster about your situation. Our insurance claims page explains how we work with adjusters on both kinds of claims.
When to call a restoration company
Whether it was a backup or a flood, the cleanup starts the same way. When you call us:
- A person answers, 24 hours a day, seven days a week.
- We ask what happened, including where the water came in and how deep it is.
- We send a crew to remove the water and start drying out your home.
- We document everything for your insurance, including where the water entered, which helps the adjuster decide which coverage applies.
When you are ready, you can contact us here.