San Francisco County— fire, flood & earthquake hazard information
San Francisco County is a county in the San Francisco Bay Area, covering about 46.7 square miles. This page summarizes what official government maps show for San Francisco County: CAL FIRE fire hazard severity zones, FEMA flood zones, state seismic hazard zones, dam inundation areas, airport noise contours, and air-quality indicators. Figures are the share of San Francisco County’s area that falls inside each mapped zone.
View San Francisco County on the interactive map → to check any specific address, free.
Wildfire hazard severity zones
CAL FIRE's current Fire Hazard Severity Zone maps do not designate any zones within San Francisco County. Individual properties near the boundary can still fall inside a neighboring zone — check the exact address on the map.
FEMA flood zones
1% of San Francisco County lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 5% is in a coastal high hazard zone (V/VE); less than 1% is in the 0.2% annual chance (500-year) area. Federally backed mortgages in a Special Flood Hazard Area generally require flood insurance.
| Special Flood Hazard Area (100-yr) | 1% |
| Coastal high hazard (V/VE) | 5% |
| 0.2% annual chance (500-yr) | less than 1% |
Earthquake faults & seismic zones
The nearest mapped fault, the Serra fault zone, is about 9.3 mi (14.9 km) from the center of San Francisco County. 4% of its area is in a state-designated liquefaction zone of required investigation. less than 1% is in an earthquake-induced landslide zone.
| Nearest mapped fault | Serra fault zone — 9.3 mi (14.9 km) |
| Liquefaction zone | 4% |
| Earthquake-induced landslide zone | less than 1% |
Dam inundation, aircraft noise & air quality
1% of San Francisco County lies within a state-reviewed dam-failure inundation area; annual average fine-particle (PM2.5) concentration across its census tracts is 8.6 μg/m³, and its composite pollution burden ranks around the 42th percentile statewide.
| Dam-failure inundation area | 1% |
| Annual PM2.5 (tract average) | 8.6 μg/m³ |
| Pollution burden percentile (statewide) | ~42 |
Frequently asked questions
- Is San Francisco County in a wildfire hazard severity zone?
- CAL FIRE's current Fire Hazard Severity Zone maps do not designate any zones within San Francisco County. Individual properties near the boundary can still fall inside a neighboring zone — check the exact address on the map.
- Is San Francisco County in a FEMA flood zone?
- 1% of San Francisco County lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 5% is in a coastal high hazard zone (V/VE); less than 1% is in the 0.2% annual chance (500-year) area. Federally backed mortgages in a Special Flood Hazard Area generally require flood insurance.
- What earthquake faults and seismic zones affect San Francisco County?
- The nearest mapped fault, the Serra fault zone, is about 9.3 mi (14.9 km) from the center of San Francisco County. 4% of its area is in a state-designated liquefaction zone of required investigation. less than 1% is in an earthquake-induced landslide zone.
- How do I check a specific address in San Francisco County?
- Use the free sitelume interactive map at https://sitelume.com — search any San Francisco County address to see which mapped zones it falls in, layer by layer.
Cities in San Francisco County
Sources: CAL FIRE Fire Hazard Severity Zones; FEMA National Flood Hazard Layer; USGS Quaternary Faults; CGS Seismic Hazard Zones & Alquist-Priolo zones; Cal OES dam inundation maps; county ALUC noise contours; CalEnviroScreen 4.0. Area shares are computed against each place’s Census TIGER boundary (last computed 2026-07-24). Boundaries and zone designations change; always verify with the issuing agency.