Coastal Flood Risk in California
All California counties ranked by FEMA National Risk Index coastal flood score
Coastal Flood risk — seawater inundation from storm surge, high tides, and rising sea levels — is rated for 20 of 58 California counties in FEMA's National Risk Index. Marin County carries the state's highest coastal flood score at 97.2, with $20M in expected annual coastal flood losses.
8 California counties are rated High or Very High for coastal flood, and expected annual losses from coastal flood total roughly $67M statewide. The full ranking below links to each county's complete 18-hazard risk profile.
County Rankings — Coastal Flood
| # | County | Coastal Flood Score | Rating | Ann. Freq. | Ann. Loss |
|---|---|---|---|---|---|
| 1 | Marin County | Very High | 1.62 / yr | $20M | |
| 2 | Orange County | High | 2.13 / yr | $8M | |
| 3 | San Mateo County | High | 0.99 / yr | $9M | |
| 4 | Los Angeles County | High | 2.17 / yr | $5M | |
| 5 | Santa Clara County | High | 0.98 / yr | $7M | |
| 6 | Humboldt County | High | 3.62 / yr | $4M | |
| 7 | Alameda County | High | 0.98 / yr | $5M | |
| 8 | Solano County | High | 2.63 / yr | $4M | |
| 9 | San Diego County | Medium | 1.65 / yr | $1M | |
| 10 | Sonoma County | Medium | 3.42 / yr | $1M | |
| 11 | Napa County | Medium | 3.61 / yr | $987K | |
| 12 | Contra Costa County | Medium | 1.53 / yr | $1M | |
| 13 | San Francisco County | Medium | 1.00 / yr | $638K | |
| 14 | Ventura County | Medium | 1.96 / yr | $599K | |
| 15 | Monterey County | Low | 3.10 / yr | $422K | |
| 16 | Mendocino County | Low | 3.23 / yr | $196K | |
| 17 | Santa Barbara County | Low | 1.14 / yr | $129K | |
| 18 | San Luis Obispo County | Low | 3.10 / yr | $136K | |
| 19 | Santa Cruz County | Low | 3.10 / yr | $117K | |
| 20 | Del Norte County | Very Low | 3.63 / yr | $25K |
20 California counties with measurable coastal flood risk. See the national coastal flood ranking or all California counties by overall risk.
Frequently Asked Questions
Which California county has the highest coastal flood risk?
Marin County has the highest FEMA coastal flood risk score in California at 97.2 (Very High), with $20M in expected annual losses and about 1.62 events per year.
How many California counties face significant coastal flood risk?
20 California counties record measurable coastal flood risk in FEMA's National Risk Index; 8 of them are rated High or Very High.