Photo: Dima Sergiyenko; Please attribute this image as the work of "DiscoverWithDima." · CC BY-SA 4.0On FEMA’s figures, Oak Brook faces less hazard damage per building than 75% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Oak Brook gets a B+ for hazard risk: lower expected damage per building than 75% of U.S. towns, #115 of 768 in Illinois. Most of that expected damage is river and rain flooding (83%), then tornadoes (12%). Flood insurance has paid 72 claims here since 1979.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What stands out about Oak Brook’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Oak Brook faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Tornadoes
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind Oak Brook’s grade
River and rain flooding is 83% of the building damage FEMA expects in Oak Brook, and Oak Brook’s rate of river and rain flooding damage is lower than 52% of U.S. census tracts. Next is tornadoes at 12% (higher than 75% of U.S. census tracts).
B+ #115 of 768 in Illinois; lower expected damage per building than 75% of U.S. towns (21,298).
Oak Brook’s residents live in 7 census tracts; FEMA’s figures are combined by where they live.
The typical Illinois town has higher expected damage than 54% of U.S. towns; within the state, Oak Brook has less expected damage per building than 85% of Illinois towns.
In dollars, FEMA expects about $5.4M a year in losses across Oak Brook: $4.1M to buildings, the rest to people and crops.
Does Oak Brook flood? Sometimes: 72 flood claims since 1979
Every paid claim on a federal flood insurance policy in Oak Brook, from FEMA’s records: 21.3 per 1,000 homes, more than 85% of the 13,809 U.S. towns with a flood insurance record.
- The Mid-spring storms11 claims · $1.2M
- Hurricane Ike3 claims · $114K
Oak Brook is in FEMA’s Community Rating System (class 7) for its flood-proofing work.
Insurance rates: DuPage County.2 federal disasters brought FEMA money to Oak Brook
Disasters that paid out in Oak Brook itself (aid to households or repair grants to the Village of Oak Brook), newest first, with that year’s flood claims.
- 2013Severe Storms, Straight-line Winds, and Flooding29 households applied for aid$70K aid approved11 flood claims paid that year
- 2010Severe Storms and Flooding97 households applied for aid$256K aid approved13 flood claims paid that year
DuPage County has had 13 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Oak Brook after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Oak Brook archive →Oak Brook and its neighbors
Oak Brook is 3rd of the 10 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Oakbrook Terrace | Aless damage than 86% | river and rain flooding | 12 |
| Westmont | A−less damage than 82% | river and rain flooding | 36 |
| Oak Brook | B+less damage than 75% | river and rain flooding | 72 |
| Downers Grove Township | B+less damage than 72% | river and rain flooding | 210 |
| Lombard | B+less damage than 68% | river and rain flooding | 94 |
| Downers Grove | Bless damage than 63% | river and rain flooding | 102 |
| York Township | Bless damage than 60% | river and rain flooding | 516 |
| Hinsdale | C+more damage than 64% | river and rain flooding | 53 |
| Elmhurst | Cmore damage than 67% | river and rain flooding | 248 |
| Proviso Township | C−more damage than 77% | river and rain flooding | 2,580 |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what Oak Brook faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Pick your spot now: the lowest floor, an inside room, no windows.
- A watch means be ready; a warning means take cover now.
- Keep shoes and a flashlight by the bed.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
- Oak Brook residents get 15% off flood insurance.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Oak Brook
Is Oak Brook at risk for natural disasters?
On FEMA’s National Risk Index, Oak Brook has lower expected damage per building than 75% of U.S. towns: B+ for hazard risk, #115 of 768 in Illinois. Most of the expected damage is river and rain flooding (83%) and tornadoes (12%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Oak Brook flood?
Flood insurance has paid 72 claims in Oak Brook since 1979, $4.2M in all, or 21.3 per 1,000 homes, more than 85% of U.S. towns with a flood insurance record. 9 properties have flooded more than once. The most claims came from Mid-spring storms (11).
Is Oak Brook in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In DuPage County, 41% of homes in mapped flood zones carry federal flood insurance, and 0.6% of all homes do.
How much is flood insurance in Oak Brook?
Oak Brook is in FEMA’s Community Rating System (class 7), which takes 15% off federal flood insurance policies for its flood-proofing work. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Oak Brook?
By FEMA money that reached Oak Brook, Severe Storms and Flooding (2010): 97 households applied for aid, $256K approved. By flood claims, Mid-spring storms: 11 paid, $1.2M.
Is Oak Brook at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (83%), and Oak Brook’s rate for it is lower than 52% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Oak Brook.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Oak Brook’s residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.