San Joaquin County, California
Natural disaster risk, federal disaster history and flood insurance facts.
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
- Ask whether an older house is bolted to its foundation.
- Consider separate earthquake insurance where risk is high.
- 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.
- Check local water restrictions.
- Choose drought-tolerant plants.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Earthquake | 99.3 | $184M | ||
| Inland flooding | 97.7 | $138M | ||
| Drought | 99.9 | $83M | ||
| Heat wave | 97.4 | $11M | ||
| Wildfire | 92.0 | $2M | ||
| Lightning | 93.4 | $2M | ||
| Tornado | 49.0 | $1M | ||
| Strong wind | 38.0 | $384K | ||
| Hail | 54.7 | $316K | ||
| Winter weather | 42.4 | $49K | ||
| Landslide | 62.0 | $3K | ||
| Volcanic activity | 79.8 | $515 | ||
| Avalanche | 2.2 | $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
Most recent
Show all 23
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.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Apr 19, 1988 | F1 | – | 0 / 0 |
| May 31, 1967 | F1 | – | 0 / 0 |
| Apr 8, 2005 | F0 | Lathrop | 0 / 0 |
| Apr 27, 1970 | F0 | – | 0 / 0 |
| Jan 23, 1981 | F0 | – | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| May 1, 1998 | Heavy Rain | Countywide | $200M |
| Jan 1, 2023 | Flood | Eagle Tree | $107M |
| May 5, 1998 | Flash Flood | Escalon | $2M |
| Apr 2, 2006 | Heavy Rain | Countywide | $1M |
| Apr 1, 1996 | Thunderstorm Wind | Stockton | $1M |
| Feb 20, 2017 | Flash Flood | Bethany | $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 ›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
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 counties | Overall risk | Top hazard |
|---|---|---|
| Los Angeles County | Earthquake | |
| San Diego County | Inland flooding | |
| Orange County | Earthquake | |
| Riverside County | Inland flooding | |
| San Bernardino County | Inland flooding | |
| Santa Clara County | Earthquake | |
| Alameda County | Earthquake | |
| Sacramento County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Alameda County | 22 | |
| Sacramento County | 21 | |
| Contra Costa County | 19 | |
| Stanislaus County | 18 | |
| Calaveras County | 22 | |
| Amador County | 19 |
Cities in San Joaquin County
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.