FEMA puts Ottawa’s expected hazard damage per building below that of 68% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Ottawa gets a B+ for hazard risk: lower expected damage per building than 68% of U.S. towns, #237 of 362 in Wisconsin. Most of that expected damage is river and rain flooding (79%), then tornadoes (11%). Flood insurance has paid 2 claims here since 2008.
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 Ottawa 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
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 Ottawa’s grade
River and rain flooding is 79% of the building damage FEMA expects in Ottawa, and Ottawa’s rate of river and rain flooding damage is higher than 50% of U.S. census tracts. Next is tornadoes at 11% (higher than 74% of U.S. census tracts).
B+ #237 of 362 in Wisconsin; lower expected damage per building than 68% of U.S. towns (21,298).
Ottawa’s residents live in 3 census tracts; FEMA’s figures are combined by where they live.
The typical Wisconsin town has lower expected damage than 79% of U.S. towns; within the state, Ottawa has more expected damage per building than 65% of Wisconsin towns.
In dollars, FEMA expects about $1.6M a year in losses across Ottawa: $1.1M to buildings, the rest to people and crops.
Does Ottawa flood? Rarely: 2 flood claims since 2008
Every paid claim on a federal flood insurance policy in Ottawa, from FEMA’s records: 1.2 per 1,000 homes, fewer than 73% of the 13,809 U.S. towns with a flood insurance record.
- The Storm1 claim · $2K
Ottawa isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Waukesha County.3 federal disasters brought FEMA money to Ottawa
Disasters that paid out in Ottawa itself (aid to households or repair grants to the Town of Ottawa), newest first, with that year’s flood claims.
- 2008Severe Storms, Tornadoes, and Flooding$11K to the Town of Ottawa for repairs
- 2008Record Snow and Near Record Snow$16K to the Town of Ottawa for repairs
- 2000Snow$12K to the Town of Ottawa for repairs
Waukesha 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 Ottawa after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Ottawa archive →Ottawa and its neighbors
Ottawa is 5th of the 7 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 |
|---|---|---|---|
| North Prairie | A−less damage than 82% | river and rain flooding | — |
| Eagle | A−less damage than 79% | river and rain flooding | 1 |
| Genesee | A−less damage than 76% | river and rain flooding | — |
| Sullivan | B+less damage than 69% | river and rain flooding | — |
| Ottawa | B+less damage than 68% | river and rain flooding | 2 |
| Summit | B+less damage than 65% | river and rain flooding | 4 |
| Dousman | Bless damage than 58% | river and rain flooding | 1 |
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 Ottawa 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.
- 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 Ottawa
Is Ottawa at risk for natural disasters?
On FEMA’s National Risk Index, Ottawa has lower expected damage per building than 68% of U.S. towns: B+ for hazard risk, #237 of 362 in Wisconsin. Most of the expected damage is river and rain flooding (79%) and tornadoes (11%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Ottawa flood?
Flood insurance has paid 2 claims in Ottawa since 2008, $14K in all, or 1.2 per 1,000 homes, fewer than 73% of U.S. towns with a flood insurance record. The most claims came from Storm (1).
Is Ottawa 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 Waukesha County, 66% of homes in mapped flood zones carry federal flood insurance, and 0.6% of all homes do.
How much is flood insurance in Ottawa?
FEMA’s Community Rating System list shows no discount for Ottawa’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 Ottawa?
By FEMA money that reached Ottawa, Record Snow and Near Record Snow (2008): $16K to the Town of Ottawa for repairs. By flood claims, Storm: 1 paid, $2K.
Is Ottawa at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (79%), and Ottawa’s rate for it is higher than 50% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Ottawa.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Ottawa’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.