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Waukesha County, Wisconsin

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively Moderate overall risk
4th of 72highest risk in Wisconsin
$138Mexpected losses a year
17federal declarations
1 in 200homes with flood insurance
Photo: U.S. Geological Survey, public domain

Waukesha County, Wisconsin has a moderate overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 89% of US counties. It ranks 4th of 72 counties in Wisconsin. The costliest hazards here are inland flooding, cold waves and tornadoes. FEMA estimates about $138 million a year in expected losses, or roughly $340 per resident. Since 1969 it has been included in 17 federal disaster or emergency declarations for natural events (13 major disasters). The most recent was in June 2026 (severe storms, tornadoes and flooding). Fewer than 1 in 100 homes here carry federal flood insurance (594 policies). Since 1978, federal flood insurance has paid about $9.4 million on 462 claims here, including $4.6 million for floods in 2025.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Waukesha County

$68.2 million a yearExpected losses. Damaging events about 2 times a year.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.
$30.3 million a yearExpected losses. Damaging events about 5 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
$23.7 million a yearExpected losses. Damaging events about once every 3 years.
  • Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
  • Turn on emergency alerts on your phone and keep a weather radio.
HazardRatingScoreExpected loss a year
Inland floodingModerate89.8
$68M
Cold waveHigh97.4
$30M
TornadoHigh95.7
$24M
HailHigh96.1
$6M
Heat waveModerate90.4
$6M
Strong windModerate56.1
$1M
Ice stormModerate81.7
$841K
EarthquakeVery Low57.4
$724K
LightningModerate60.2
$606K
Winter weatherHigh86.5
$553K
WildfireVery Low49.7
$83K
DroughtLow31.6
$55K
LandslideLow62.5
$6K
HurricaneVery Low9.7
$3K

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is very low and community resilience is very high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Waukesha County. 2020s bar runs to November 2026.

By type

Flood7
Severe Storm6
Snowstorm2
Drought1
Hurricane1

Most recent

Jun 30, 2026Severe Storms, Tornadoes, and FloodingMajor disaster
Sep 11, 2025Severe Storms, Straight-Line Winds, Flooding, and MudslidesMajor disaster
Jun 14, 2008Severe Storms, Tornadoes, and FloodingMajor disaster
Mar 19, 2008Record Snow and Near Record SnowEmergency
Sep 13, 2005Hurricane Katrina EvacuationEmergency
Jun 18, 2004Severe Storms and FloodingMajor disaster
Jan 24, 2001SnowEmergency
Jun 24, 2000Severe Storms, Tornadoes, and FloodingMajor disaster
Aug 12, 1998Severe Storms and FloodingMajor disaster
Jul 7, 1997Severe Storms and FloodingMajor disaster
Show all 17
Aug 6, 1991Severe Storms & HailMajor disaster
Oct 7, 1986Severe Storms & FloodingMajor disaster
Aug 14, 1986Severe StormsMajor disaster
Jun 17, 1976DroughtEmergency
Mar 23, 1976Severe Storms, Icing, Wind & FloodingMajor disaster
Apr 27, 1973Severe Storms & FloodingMajor disaster
Jul 11, 1969Severe Storms & FloodingMajor disaster

Wisconsin also had 8 statewide declarations that did not name single counties.

Storm history since 1954

Tornado risk by county ›

The National Weather Service has logged 793 storm reports in Waukesha County since 1954, with 5 deaths and 47 injuries and about $279 million in reported damage. The strongest on record here was an F4 tornado on April 27, 1984.

40tornadoes
264hail reports, largest 3.75 inches
356damaging thunderstorm winds
60floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Apr 27, 1984F4–14 / 1
Jun 5, 1977F3–0 / 0
Jun 5, 1980F3–0 / 0
Jun 21, 2010EF2Eagle15 / 0
Apr 14, 2026EF2Merton0 / 0

Most damaging storms

DateTypeNearDamage
Aug 9, 2025Flash FloodMenomonee Falls$89M
Jun 8, 2008Flash FloodNorth Prairie$64M
Jun 21, 2010TornadoEagle$21M
Aug 6, 1998Flash FloodBrookfield$17M
Aug 9, 2025Flash FloodMenomonee Falls$9M
Apr 14, 2026TornadoMerton$7M

Source: NOAA Storm Events Database, county-based reports through Jul 27, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Flood insurance in Waukesha County

Check your address flood zone ›
0.5%of homes have federal flood insurance (594 policies)
66.5%of homes in mapped high-risk flood zones are insured
$9.4 millionpaid on 462 flood claims since 1978
2025costliest year, with $4.6 million paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Waukesha County

$398,200median home value (Wisconsin $266,500, US $332,700)
1981median year homes were built (Wisconsin 1975, US 1980)
48%of homes built before 1980, before many modern wind, quake and flood building rules
0.6%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 175,591 housing units.

Compare in Wisconsin

All 72 ›
Largest countiesOverall riskTop hazard
Milwaukee CountyHighCold wave
Dane CountyModerateInland flooding
Waukesha CountyModerateInland flooding
Brown CountyModerateInland flooding
Racine CountyModerateInland flooding
Outagamie CountyLowInland flooding
Winnebago CountyModerateInland flooding
Kenosha CountyModerateCold wave

Neighboring counties

CountyOverall riskDeclarations
Milwaukee CountyHigh20
Racine CountyModerate15
Washington CountyLow12
Walworth CountyLow11
Ozaukee CountyLow11
Dodge CountyLow11
Jefferson CountyLow12

Common questions about Waukesha County

What is the biggest natural hazard in Waukesha County?

Inland flooding has the highest expected yearly losses in Waukesha County, about $68.2 million a year in FEMA's estimate. Cold wave is second at $30.3 million.

How many federal disasters has Waukesha County had?

Waukesha County has been included in 17 federal disaster or emergency declarations for natural events since 1969, including 13 major disasters. The most recent was Severe Storms, Tornadoes, and Flooding in June 2026.

Is Waukesha County a high-risk place to live?

Its overall rating is Relatively Moderate, 4th highest of 72 in Wisconsin. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Waukesha County?

Standard home insurance does not cover flooding. About 1 in 200 homes in Waukesha County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Waukesha County had?

NOAA records list 40 tornadoes in Waukesha County since 1950. The strongest was an F4 tornado on April 27, 1984. The weather service has also logged 264 hail reports and 60 floods here.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.