South San Francisco, CA— fire, flood & earthquake hazard information
South San Francisco is a city in San Mateo County in the San Francisco Bay Area, covering about 9.2 square miles. This page summarizes what official government maps show for South San Francisco: 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 South San Francisco’s area that falls inside each mapped zone.
View South San Francisco 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 South San Francisco. Individual properties near the boundary can still fall inside a neighboring zone — check the exact address on the map.
FEMA flood zones
6% of South San Francisco lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 4% is in a coastal high hazard zone (V/VE); 2% 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) | 6% |
| Coastal high hazard (V/VE) | 4% |
| 0.2% annual chance (500-yr) | 2% |
Earthquake faults & seismic zones
The nearest mapped fault, the Serra fault zone, is about 5.4 mi (8.7 km) from the center of South San Francisco. 2 named fault traces in the USGS Quaternary fault database cross its boundary. 11% of its area is in a state-designated liquefaction zone of required investigation. 3% is in an earthquake-induced landslide zone. less than 1% falls within an Alquist-Priolo earthquake fault zone, where new construction requires a fault study.
| Nearest mapped fault | Serra fault zone — 5.4 mi (8.7 km) |
| Named fault traces crossing boundary | 2 |
| Liquefaction zone | 11% |
| Earthquake-induced landslide zone | 3% |
| Alquist-Priolo fault zone | less than 1% |
Dam inundation, aircraft noise & air quality
15% is inside an airport noise contour of 65 dB CNEL or louder; annual average fine-particle (PM2.5) concentration across its census tracts is 8.7 μg/m³, and its composite pollution burden ranks around the 66th percentile statewide.
| Airport noise ≥65 dB CNEL | 15% |
| Annual PM2.5 (tract average) | 8.7 μg/m³ |
| Pollution burden percentile (statewide) | ~66 |
Frequently asked questions
- Is South San Francisco in a wildfire hazard severity zone?
- CAL FIRE's current Fire Hazard Severity Zone maps do not designate any zones within South San Francisco. Individual properties near the boundary can still fall inside a neighboring zone — check the exact address on the map.
- Is South San Francisco in a FEMA flood zone?
- 6% of South San Francisco lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 4% is in a coastal high hazard zone (V/VE); 2% 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 South San Francisco?
- The nearest mapped fault, the Serra fault zone, is about 5.4 mi (8.7 km) from the center of South San Francisco. 2 named fault traces in the USGS Quaternary fault database cross its boundary. 11% of its area is in a state-designated liquefaction zone of required investigation. 3% is in an earthquake-induced landslide zone. less than 1% falls within an Alquist-Priolo earthquake fault zone, where new construction requires a fault study.
- How do I check a specific address in South San Francisco?
- Use the free sitelume interactive map at https://sitelume.com — search any South San Francisco address to see which mapped zones it falls in, layer by layer.
Nearby in San Mateo 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.