Photo: Robert Lawton · CC BY-SA 2.5On FEMA’s figures, O'Fallon Township faces more hazard damage per building than 64% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, O'Fallon Township gets a C+ for hazard risk: higher expected damage per building than 64% of U.S. towns, #500 of 768 in Illinois. Most of that expected damage is river and rain flooding (57%), then earthquakes (27%). Flood insurance has paid 10 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 O'Fallon Township 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
Earthquakes
Tornadoes
Hail
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 O'Fallon Township’s grade
River and rain flooding is 57% of the building damage FEMA expects in O'Fallon Township, and O'Fallon Township’s rate of river and rain flooding damage is higher than 56% of U.S. census tracts. Next is earthquakes at 27% (higher than 84% of U.S. census tracts).
C+ #500 of 768 in Illinois; higher expected damage per building than 64% of U.S. towns (21,298).
O'Fallon Township’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, O'Fallon Township has more expected damage per building than 65% of Illinois towns.
In dollars, FEMA expects about $11.9M a year in losses across O'Fallon Township: $6.6M to buildings, the rest to people and crops.
Does O'Fallon Township flood? Sometimes: 10 flood claims since 1979
Every paid claim on a federal flood insurance policy in O'Fallon Township, from FEMA’s records: 0.9 per 1,000 homes, fewer than 80% of the 13,809 U.S. towns with a flood insurance record.
- The Mid-spring storms3 claims · $7K
- The Late July Flooding1 claim · $7K
O'Fallon Township isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: St. Clair County.The storms O'Fallon Township remembers
None of the 16 disasters declared for St. Clair County shows FEMA aid or repair money reaching O'Fallon Township itself in FEMA’s records, so these are its biggest flood-claim years.
- 20133 flood claims paidNo declaration for the county that year
- 19791 flood claims paidThe year of Severe Storms and Flooding, declared for St. Clair County
- 19861 flood claims paidThe year of Severe Storms and Flooding, declared for St. Clair County
St. Clair County has had 16 natural disasters declared by the President since 1953, most often floods, then severe storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of O'Fallon Township after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the O'Fallon Township archive →O'Fallon Township and its neighbors
O'Fallon Township is 3rd of the 6 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 |
|---|---|---|---|
| Jarvis Township | C+more damage than 60% | river and rain flooding | 3 |
| O'Fallon | C+more damage than 63% | river and rain flooding | 12 |
| O'Fallon Township | C+more damage than 64% | river and rain flooding | 10 |
| Caseyville Township | Cmore damage than 67% | river and rain flooding | 51 |
| Shiloh Valley Township | Cmore damage than 74% | river and rain flooding | 1 |
| Shiloh | Cmore damage than 74% | river and rain flooding | 2 |
| Lebanon Township | — | not graded yet | |
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 O'Fallon Township 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.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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.
- Park in a garage or under cover when storms are forecast.
- Stay away from windows while it falls.
- Photograph roof and car damage for your insurer.
- 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.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in O'Fallon Township
Is O'Fallon Township at risk for natural disasters?
On FEMA’s National Risk Index, O'Fallon Township has higher expected damage per building than 64% of U.S. towns: C+ for hazard risk, #500 of 768 in Illinois. Most of the expected damage is river and rain flooding (57%) and earthquakes (27%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does O'Fallon Township flood?
Flood insurance has paid 10 claims in O'Fallon Township since 1979, $40K in all, or 0.9 per 1,000 homes, fewer than 80% of U.S. towns with a flood insurance record. The most claims came from Mid-spring storms (3).
Is O'Fallon Township 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 St. Clair County, 1.0% of all homes carry federal flood insurance.
How much is flood insurance in O'Fallon Township?
FEMA’s Community Rating System list shows no discount for O'Fallon Township’s flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in O'Fallon Township?
By flood claims, Mid-spring storms: 3 paid, $7K.
Is O'Fallon Township at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (57%), and O'Fallon Township’s rate for it is higher than 56% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in O'Fallon Township.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where O'Fallon Township’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.