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San Joaquin County, California

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

Relatively High overall risk
17th of 58highest risk in California
$422Mexpected losses a year
23federal declarations
1 in 56homes with flood insurance
Photo: Quintin Soloviev, CC BY 4.0

San Joaquin County, California has a relatively high overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 99% of US counties. It ranks 17th of 58 counties in California. The costliest hazards here are earthquakes, inland flooding and drought. FEMA estimates about $422 million a year in expected losses, or roughly $542 per resident. Since 1964 it has been included in 23 federal disaster or emergency declarations for natural events (18 major disasters). The most recent was in April 2023 (severe winter storms, straight-line winds, flooding, landslides and mudslides). About 1 in 56 homes here carry federal flood insurance (3,840 policies). Since 1978, federal flood insurance has paid about $8.1 million on 421 claims here, including $2.6 million for floods in 1997.

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

Top risks in San Joaquin County

$184 million a yearExpected losses. Damaging events about once every 9 years.
  • Ask whether an older house is bolted to its foundation.
  • Consider separate earthquake insurance where risk is high.
$138 million a yearExpected losses. Damaging events about once 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.

Drought

Very High
$83.3 million a yearExpected losses. Damaging events about 69 times a year.
  • Check local water restrictions.
  • Choose drought-tolerant plants.
HazardRatingScoreExpected loss a year
EarthquakeHigh99.3
$184M
Inland floodingHigh97.7
$138M
DroughtVery High99.9
$83M
Heat waveHigh97.4
$11M
WildfireModerate92.0
$2M
LightningHigh93.4
$2M
TornadoLow49.0
$1M
Strong windLow38.0
$384K
HailLow54.7
$316K
Winter weatherLow42.4
$49K
LandslideVery Low62.0
$3K
Volcanic activityVery Low79.8
$515
AvalancheVery Low2.2
$0

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 relatively low and community resilience is relatively moderate in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

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

By type

Flood10
Severe Storm6
Coastal Storm2
Drought1
Earthquake1
Freezing1

Most recent

Apr 3, 2023Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and MudslidesMajor disaster
Mar 10, 2023Severe Winter Storms, Flooding, Landslides, and MudslidesEmergency
Jan 14, 2023Severe Winter Storms, Flooding, Landslides, and MudslidesMajor disaster
Jan 9, 2023Severe Winter Storms, Flooding, and MudslidesEmergency
Apr 1, 2017Severe Winter Storms, Flooding, and MudslidesMajor disaster
Jun 5, 2006Severe Storms, Flooding, Landslides, and MudslidesMajor disaster
Feb 3, 2006Severe Storms, Flooding, Mudslides, and LandslidesMajor disaster
Sep 13, 2005Hurricane Katrina EvacuationEmergency
Jun 30, 2004Flooding As A Result of A Levee BreakMajor disaster
Feb 9, 1998Severe Winter Storms and FloodingMajor disaster
Show all 23
Jan 4, 1997Severe Storms, Flooding, Mud and LandslidesMajor disaster
Mar 12, 1995Severe Winter Storms, Flooding Landslides, Mud FlowMajor disaster
Feb 11, 1991Severe FreezeMajor disaster
Oct 18, 1989Loma Prieta EarthquakeMajor disaster
Feb 21, 1986Severe Storms & FloodingMajor disaster
Feb 9, 1983Coastal Storms, Floods, Slides & TornadoesMajor disaster
Sep 24, 1982Levee BreakMajor disaster
Jan 7, 1982Severe Storms, Flood, Mudslides & High TideMajor disaster
Oct 2, 1980Levee Break & FloodingMajor disaster
Feb 1, 1980Torrential Rain, High Tide & WindsEmergency
Jan 20, 1977DroughtEmergency
Jan 26, 1969Severe Storms & FloodingMajor disaster
Dec 24, 1964Heavy Rains & FloodingMajor disaster

California also had 35 statewide declarations that did not name single counties.

Storm history since 1967

Tornado risk by county ›

The National Weather Service has logged 102 storm reports in San Joaquin County since 1967, with 0 deaths and 4 injuries and about $312 million in reported damage. The strongest on record here was an F1 tornado on April 19, 1988.

19tornadoes
5hail reports, largest 1 inches
4damaging thunderstorm winds
53floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Apr 19, 1988F1–0 / 0
May 31, 1967F1–0 / 0
Apr 8, 2005F0Lathrop0 / 0
Apr 27, 1970F0–0 / 0
Jan 23, 1981F0–0 / 0

Most damaging storms

DateTypeNearDamage
May 1, 1998Heavy RainCountywide$200M
Jan 1, 2023FloodEagle Tree$107M
May 5, 1998Flash FloodEscalon$2M
Apr 2, 2006Heavy RainCountywide$1M
Apr 1, 1996Thunderstorm WindStockton$1M
Feb 20, 2017Flash FloodBethany$500K

Source: NOAA Storm Events Database, county-based reports through Apr 21, 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 San Joaquin County

Check your address flood zone ›
1.8%of homes have federal flood insurance (3,840 policies)
24.7%of homes in mapped high-risk flood zones are insured
$8.1 millionpaid on 421 flood claims since 1978
1997costliest year, with $2.6 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 San Joaquin County

$530,700median home value (California $734,700, US $332,700)
1984median year homes were built (California 1976, US 1980)
44%of homes built before 1980, before many modern wind, quake and flood building rules
3.1%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; 260,151 housing units.

Compare in California

All 58 ›
Largest countiesOverall riskTop hazard
Los Angeles CountyVery HighEarthquake
San Diego CountyVery HighInland flooding
Orange CountyVery HighEarthquake
Riverside CountyVery HighInland flooding
San Bernardino CountyVery HighInland flooding
Santa Clara CountyVery HighEarthquake
Alameda CountyVery HighEarthquake
Sacramento CountyHighInland flooding

Neighboring counties

CountyOverall riskDeclarations
Alameda CountyVery High22
Sacramento CountyHigh21
Contra Costa CountyVery High19
Stanislaus CountyHigh18
Calaveras CountyModerate22
Amador CountyLow19

Common questions about San Joaquin County

What is the biggest natural hazard in San Joaquin County?

Earthquake has the highest expected yearly losses in San Joaquin County, about $184 million a year in FEMA's estimate. Inland flooding is second at $138 million.

How many federal disasters has San Joaquin County had?

San Joaquin County has been included in 23 federal disaster or emergency declarations for natural events since 1964, including 18 major disasters. The most recent was Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides in April 2023.

Is San Joaquin County a high-risk place to live?

Its overall rating is Relatively High, 17th highest of 58 in California. 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 San Joaquin County?

Standard home insurance does not cover flooding. About 1 in 56 homes in San Joaquin 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 San Joaquin County had?

NOAA records list 19 tornadoes in San Joaquin County since 1950. The strongest was an F1 tornado on April 19, 1988. The weather service has also logged 5 hail reports and 53 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.