462 flood insurance claims·$9.3M paid·6 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 Waukesha 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 dominates the flood risk profile in Waukesha County. Over the last 30 years, the NOAA Storm Events Database recorded 36 flash flood events resulting in 3 deaths, alongside 25 general flood events. A historic flash flood and record rainfall occurred in August 2025, driven by warm, moist, and unstable air rising along a stalled front to produce numerous thunderstorms, more than 10 inches of rain in many locations, and widespread flooding of streets, creeks, rivers, and low-lying neighborhoods across Southeast Wisconsin, resulting in damages in the hundreds of millions of dollars.
National Flood Insurance Program claims data demonstrate that flood risks extend beyond high-risk areas. Zone A accounts for 245 claims with an average payout of $33,088 and an average recorded water depth of 11 inches. However, properties outside designated high-risk zones also experience losses; Zone X recorded 127 claims with an average payout of $19,660 and an average water depth of 10 inches, Unshaded Zone X recorded 50 claims averaging $14,933 with an average water depth of 8 inches, Unknown zones recorded 27 claims averaging $3,143 with an average water depth of 4 inches, and Shaded Zone X recorded 13 claims averaging $13,461 with an average water depth of 2 inches. Property owners in Zone A and moderate-to-low risk Zone X areas should pay the most attention to flood risk given the documented claim history.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
20% of Waukesha County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
308 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 10 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 112 claims and $1.8M 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.
44 NOAA storm reports from Waukesha County describe what happened, in the words of the forecasters who covered it. Read the Wisconsin flood stories →
18 federal disaster declarations since 1969, 6 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Straight-line Winds, Flooding, And Mudslides | Aug 9, 2025 |
| 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 |
| Severe Storms And Flooding | Aug 5, 1998 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
61 since 1996: 36 flash floods and 25 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Aug 10, 2025 | $1,000 |
| Flood | Aug 10, 2025 | $1.0M |
| Flash Flood | Aug 9, 2025 | $9.0M |
| Flash Flood | Aug 9, 2025 | $89.0M |
| Flood | Aug 14, 2023 | $1,000 |
| Flood | Jun 15, 2022 | $1,000 |
| Flood | Sep 11, 2022 | $25,000 |
| Flood | Jun 10, 2022 | $30,000 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Aug 10, 2025. A historic flash flood and record rainfall occurred over portions of the Milwaukee Metropolitan Area and Southeast WI resulting in damages in the $100s Millions. Warm, moist, and unstable air rose along a stalled front to produce numerous thunderstorms and more than 10 inches of rain in many locations. Widespread flash flooding of streets, creeks, rivers, and low lying neighborhoods occurred. A homeless camp in Mi…
Flood · Aug 10, 2025. A historic flash flood and record rainfall occurred over portions of the Milwaukee Metropolitan Area and Southeast WI resulting in damages in the $100s Millions. Warm, moist, and unstable air rose along a stalled front to produce numerous thunderstorms and more than 10 inches of rain in many locations. Widespread flash flooding of streets, creeks, rivers, and low lying neighborhoods occurred. A homeless camp in Mi…
Flash Flood · Aug 9, 2025. A historic flash flood and record rainfall occurred over portions of the Milwaukee Metropolitan Area and Southeast WI resulting in damages in the $100s Millions. Warm, moist, and unstable air rose along a stalled front to produce numerous thunderstorms and more than 10 inches of rain in many locations. Widespread flash flooding of streets, creeks, rivers, and low lying neighborhoods occurred. A homeless camp in Mi…
Flood · Aug 14, 2023. A slow moving, strong low pressure area brought several hours of moderate to heavy rainfall to southern WI. Street flooding occurred in urban areas.
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 Waukesha 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.