46 flood insurance claims·$646,644 paid·2 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Walworth County, Wisconsin. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Flash flooding from summer thunderstorms and general flooding dominate the flood profile in Walworth County, backed by 17 flash flood events and 15 flood events recorded over the last 30 years in the NOAA Storm Events Database. Recent weather systems have caused notable high-water events, including rounds of heavy thunderstorms that dropped 4 to 6 inches of rain leading to flash flooding on June 18, 2025, and a slow-moving cold front that caused flooding on August 18, 2025. Additional flooding occurred on April 4, 2023, due to severe thunderstorms, and on April 29, 2020, from a slow-moving low-pressure system that brought several inches of rain resulting in road, river, and lake flooding.
National Flood Insurance Program records show that flood claims are not limited to high-risk areas. Zone X properties recorded 32 claims with an average payout of $20,747 and an average recorded water depth of 1 inch. Zone A properties accounted for 7 claims with an average payout of $23,993 and an average recorded water depth of 4 inches. Zone X_UNSHADED properties filed 2 claims with an average payout of $3,990 and an average recorded water depth of 8 inches, while Zone UNKNOWN properties recorded 5 claims with an average payout of $388 and an average recorded water depth of 2 inches. Homeowners, real estate agents, and journalists should note that properties in both mapped high-risk zones like Zone A and moderate-to-low risk zones like Zone X experience damaging water accumulation during heavy rainfall events.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
In flood insurance claims here that reported a flood depth, the average was 2 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2020, with 11 claims and $187,164 paid.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
22 NOAA storm reports from Walworth County describe what happened, in the words of the forecasters who covered it. Read the Wisconsin flood stories →
13 federal disaster declarations since 1965, 2 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Winter Storm And Snowstorm | Jan 31, 2011 |
| Severe Storms, Tornadoes, And Flooding | Jun 5, 2008 |
| Record Snow And Near Record Snow | Feb 5, 2008 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Severe Storms And Flooding | May 7, 2004 |
| Snow | Dec 11, 2000 |
| Severe Storms, Tornadoes, And Flooding | May 26, 2000 |
| Drought | Jun 17, 1976 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
32 since 1996: 17 flash floods and 15 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 18, 2025 | $10,000 |
| Flood | Aug 18, 2025 | $2,000 |
| Flood | Apr 4, 2023 | $1,000 |
| Flood | Apr 29, 2020 | $50,000 |
| Flash Flood | Aug 10, 2020 | $1,000 |
| Flood | Sep 13, 2019 | $20,000 |
| Flash Flood | Sep 12, 2019 | $15,000 |
| Flood | Feb 20, 2018 | $5,000 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jun 18, 2025. Low pressure tracking from northern Missouri to southern Lake MI spread rounds of thunderstorms across far southern WI. This eventually led to flash flooding in Rock and Walworth Counties after 4-6 inches of rain had fallen.
Flood · Aug 18, 2025. Numerous thunderstorms and heavy rain ahead of a slow moving cold front caused some flooding in southern Rock and Walworth Counties.
Flood · Apr 4, 2023. Rounds of strong to severe thunderstorms occurred across southern WI, as low pressure and its warm and cold fronts approached and moved across the region. Many large hail reports were received along with one EF0 tornado. Some damaging winds and flooding also occurred.
Flood · Apr 29, 2020. A slow moving low pressure area brought several inches of rain to far eastern WI over a 24-40 hour period. River and lake flooding occurred along with some road flooding.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Walworth County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.