305 flood insurance claims·$4.2M 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 Rock 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.
Standard riverine flooding combined with flash flooding from summer thunderstorms dominates Rock County, as recorded by 62 flood events and 23 flash flood events over the last 30 years. Recent impacts include urban and small stream flooding in Janesville following thunderstorms on June 29, 2025, and flash flooding caused by 4 to 6 inches of rainfall across Rock and Walworth counties on June 18, 2025. Severe storms on June 22, 2024, also produced multiple flash flood reports alongside tornado damage in Janesville.
Homeowners, real estate agents, and journalists should pay the closest attention to properties located in FEMA Zone A, which accounts for the vast majority of local National Flood Insurance Program claims. Zone A properties recorded 198 claims with an average payout of $21,365 and an average recorded water depth of 13 inches. Properties in moderate-to-low risk zones—including Zone X (33 claims averaging an 8-inch average water depth), unshaded Zone X (30 claims averaging a 15-inch average water depth), and shaded Zone X (15 claims averaging a 20-inch average water depth)—have also experienced historical flood claims and payouts, indicating that flood risk extends beyond designated high-risk zones.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
19% of Rock County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
243 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 12 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 2008, with 139 claims and $3.4M paid, the year of Severe Storms, Tornadoes, and Flooding.
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.
41 NOAA storm reports from Rock County describe what happened, in the words of the forecasters who covered it. Read the Wisconsin flood stories →
15 federal disaster declarations since 1973, 2 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Tornadoes, And Flooding | Jun 5, 2008 |
| Record Snow And Near Record Snow | Feb 5, 2008 |
| Severe Storms And Flooding | Aug 18, 2007 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Severe Storms And Flooding | May 7, 2004 |
| Snow | Dec 11, 2000 |
| Severe Storms And Flooding | Aug 5, 1998 |
| Severe Storms, Tornadoes & Flooding | Jun 7, 1993 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
85 since 1996: 23 flash floods and 62 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flood | Jun 29, 2025 | $1,000 |
| Flash Flood | Jun 18, 2025 | $5,000 |
| Flash Flood | Aug 18, 2025 | $50,000 |
| Flash Flood | Jun 22, 2024 | $20,000 |
| Flood | Jul 15, 2024 | $1,000 |
| Flood | Jul 14, 2024 | $1,000 |
| Flood | Jul 14, 2024 | $2,000 |
| Flash Flood | Jun 3, 2024 | $15,000 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flood · Jun 29, 2025. Numerous thunderstorms erupted over southern WI ahead of a slow moving cold front. Damaging downburst winds occurred in and around Timmerman Field in Milwaukee. Urban and small stream flooding occurred in Pardeeville and Janesville.
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.
Flash 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.
Flash Flood · Jun 22, 2024. Severe thunderstorms developed across western Wisconsin and moved eastward across southern Wisconsin through the afternoon and evening hours on June 22nd due to passing low pressure and its approaching cold front. There were supercell thunderstorms along with bowing segments along this line which lead to multiple areas of damage. Two strong tornadoes occurred, which were rated EF-2 near Argyle and through the so…
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 Rock 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.