Updated May 2026
Flood Risk in California
California carries a relatively low statewide average risk score of 14, with 100% of its 59 counties at A or B. 0 counties are in the F (extreme) tier, typically along major rivers or flood-prone basins. Statewide NFIP take-up is modest at 1.2K total claims.
Grade Distribution Across California
The grade mix is dominated by A — 93% of counties — meaning the typical place in this state has very low historical flood loss. The handful of B/C/D/F counties below define where risk is concentrated.
How California Compares Nationally
The U.S. county-level average composite score is 12. California sits at 14, which is right around the national average. 556 federal flood-related disaster declarations across 59 counties is one of the highest counts in the dataset — about 9.4 per county. Most counties have lived through multiple federally declared floods.
For full national context — every state ranked by average score and total claims — see the all-states overview. The riskiest-counties ranking and highest-payouts ranking drill into where loss is concentrated. Real-time stream-gauge readings are at USGS Water Data.
Riskiest in California
| County | Grade | Score |
|---|---|---|
| San Joaquin | B | 22 |
| Contra Costa | B | 21 |
| Santa Cruz | B | 21 |
| Sonoma | B | 21 |
| El Dorado | A | 20 |
Safest in California
| County | Grade | Score |
|---|---|---|
| Placer | A | 8 |
| Santa Barbara | A | 10 |
| Orange | A | 10 |
| San Francisco | A | 10 |
| Alpine | A | 11 |
How California's Risk Is Calculated
Every county in California is scored on the same four factors that drive every county nationwide: NFIP claims density (40%), federally declared flood-disaster frequency (25%), average claim severity (20%), and year-over-year trend (15%). Source data comes from the public FEMA flood-mapping program and OpenFEMA endpoints. Detailed weighting math, plus the data's known limitations (county-level granularity, NFIP-participation bias, historical bias), is on the methodology page.
All 59 Counties in California
Sorted by flood risk score, highest to lowest.
| # | County | Grade | Score | Claims | Payouts | Disasters |
|---|---|---|---|---|---|---|
| 1 | San Joaquin | B | 22 | 17 | $1,095,649 | 13 |
| 2 | Contra Costa | B | 21 | 30 | $1,005,011 | 11 |
| 3 | Santa Cruz | B | 21 | 69 | $2,554,213 | 10 |
| 4 | Sonoma | B | 21 | 147 | $3,994,861 | 11 |
| 5 | El Dorado | A | 20 | 16 | $231,990 | 9 |
| 6 | Shasta | A | 20 | 10 | $376,319 | 9 |
| 7 | Tulare | A | 20 | 21 | $452,898 | 9 |
| 8 | Lake | A | 19 | 28 | $348,743 | 8 |
| 9 | Monterey | A | 19 | 28 | $1,908,777 | 10 |
| 10 | San Mateo | A | 19 | 33 | $1,995,914 | 9 |
| 11 | Santa Clara | A | 19 | 39 | $1,153,987 | 8 |
| 12 | Alameda | A | 18 | 24 | $323,458 | 9 |
| 13 | Kern | A | 17 | 13 | $116,930 | 10 |
| 14 | Los Angeles | A | 17 | 163 | $3,719,626 | 12 |
| 15 | Humboldt | A | 15 | 3 | $110,201 | 14 |
| 16 | Mendocino | A | 15 | 1 | $0 | 13 |
| 17 | Riverside | A | 15 | 22 | $257,431 | 16 |
| 18 | Ventura | A | 15 | 26 | $542,994 | 12 |
| 19 | San Luis Obispo | A | 14 | 18 | $747,666 | 12 |
| 20 | San Bernardino | A | 14 | 20 | $172,950 | 15 |
| 21 | Del Norte | A | 13 | 0 | $0 | 10 |
| 22 | Glenn | A | 13 | 0 | $0 | 10 |
| 23 | Marin | A | 13 | 34 | $446,575 | 11 |
| 24 | Napa | A | 13 | 1 | $23,534 | 10 |
| 25 | Trinity | A | 13 | 0 | $0 | 11 |
| 26 | San Diego | A | 13 | 99 | $3,795,338 | 14 |
| 27 | Tule River Indian Reservation | A | 12 | 0 | $0 | 9 |
| 28 | Butte | A | 12 | 7 | $278,496 | 8 |
| 29 | Colusa | A | 12 | 5 | $95,517 | 8 |
| 30 | Kings | A | 12 | 1 | $0 | 9 |
| 31 | Modoc | A | 12 | 0 | $0 | 8 |
| 32 | Mono | A | 12 | 1 | $0 | 8 |
| 33 | Plumas | A | 12 | 2 | $0 | 8 |
| 34 | Sacramento | A | 12 | 71 | $1,172,762 | 12 |
| 35 | San Benito | A | 12 | 13 | $169,821 | 8 |
| 36 | Siskiyou | A | 12 | 0 | $0 | 8 |
| 37 | Stanislaus | A | 12 | 2 | $0 | 8 |
| 38 | Sutter | A | 12 | 7 | $7,564 | 8 |
| 39 | Tehama | A | 12 | 8 | $379,743 | 11 |
| 40 | Tuolumne | A | 12 | 4 | $40,070 | 8 |
| 41 | Yolo | A | 12 | 5 | $31,938 | 8 |
| 42 | Yuba | A | 12 | 5 | $128,321 | 9 |
| 43 | Inyo | A | 12 | 0 | $0 | 9 |
| 44 | Alpine | A | 11 | 0 | $0 | 7 |
| 45 | Amador | A | 11 | 3 | $340,594 | 7 |
| 46 | Calaveras | A | 11 | 4 | $39,702 | 6 |
| 47 | Lassen | A | 11 | 4 | $18,560 | 6 |
| 48 | Mariposa | A | 11 | 0 | $0 | 7 |
| 49 | Merced | A | 11 | 40 | $1,704,934 | 7 |
| 50 | Nevada | A | 11 | 2 | $94,416 | 6 |
| 51 | Sierra | A | 11 | 2 | $3,326 | 7 |
| 52 | Solano | A | 11 | 12 | $509,065 | 10 |
| 53 | Fresno | A | 11 | 3 | $156,499 | 7 |
| 54 | Imperial | A | 11 | 0 | $0 | 6 |
| 55 | Madera | A | 11 | 1 | $0 | 7 |
| 56 | Santa Barbara | A | 10 | 63 | $2,948,611 | 15 |
| 57 | Orange | A | 10 | 38 | $512,968 | 13 |
| 58 | San Francisco | A | 10 | 4 | $384,370 | 4 |
| 59 | Placer | A | 8 | 7 | $56,882 | 8 |
Frequently Asked Questions
What is the average flood risk score in California?
California's average composite flood risk score is 14 on a 0–100 scale, computed as the mean of all 59 county scores. That is roughly equal to the U.S. county-level average of 12. Score components: 40% claims density, 25% disaster frequency, 20% claim severity, 15% trend.
Which counties in California have the highest flood risk?
The riskiest county in California is San Joaquin with a composite score of 22 (grade B). The next four — Contra Costa, Santa Cruz, Sonoma, El Dorado — round out the top-five most exposed places in the state.
How many NFIP flood-insurance claims has California filed?
FEMA's National Flood Insurance Program shows 1.2K claims on file from California, with combined payouts of $34,449,224 across the dataset. 49 of the state's 59 counties have at least one NFIP claim recorded.
Are FEMA flood maps the same as your risk score?
No. The flood risk score on this page is a county-wide composite drawn from claims, disasters, severity, and trend. FEMA Flood Insurance Rate Maps (FIRMs, available at fema.gov/flood-maps) are parcel-level zone designations based on hydrologic modeling. The two answer different questions; serious decisions about insurance or building should use both, plus real-time hydrology from USGS Water Data.
When was the California data last updated?
These figures were refreshed from the OpenFEMA API on 2026-05-16. FEMA itself publishes new NFIP claims on a quarterly cycle, so the data may lag actual events by up to three months.
Flood risk profile for California: 59 counties, 1.2K NFIP claims, average composite score 14.
The this entity record above pulls directly from FEMA OpenFEMA datasets including the National Flood Hazard Layer and NFIP claims. What follows is the per-entity context — how this entity sits in the broader U.S. flood risk, NFIP claims, and disaster declarations distribution and which underlying factors drive the headline numbers.
The methodology behind every numeric value on this page is publicly documented on the FEMA OpenFEMA datasets including the National Flood Hazard Layer and NFIP claims portal and described in detail on this site’s methodology page. Refresh cadence varies by underlying series; the page surfaces the as-of date for each number so readers can trace any figure back to the source release.
Practical use of this page is in combination with the comparison and ranking pages elsewhere on the site, which surface the same data for this entity’s peers within U.S. ZIPs, counties, and states. A single-entity reading without peer context can be misleading when an entity is an outlier on one axis but typical on another.