San Miguel, CA— fire, flood & earthquake hazard information
San Miguel is a unincorporated community in Contra Costa County in the San Francisco Bay Area, covering about 1.1 square miles. This page summarizes what official government maps show for San Miguel: 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 Miguel’s area that falls inside each mapped zone.
View San Miguel 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 Miguel. Individual properties near the boundary can still fall inside a neighboring zone — check the exact address on the map.
FEMA flood zones
6% of San Miguel lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 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) | 6% |
| 0.2% annual chance (500-yr) | less than 1% |
Earthquake faults & seismic zones
The nearest mapped fault, the Mount Diablo thrust fault, is about 0.9 mi (1.4 km) from the center of San Miguel. 48% of its area is in a state-designated liquefaction zone of required investigation. 3% is in an earthquake-induced landslide zone.
| Nearest mapped fault | Mount Diablo thrust fault — 0.9 mi (1.4 km) |
| Liquefaction zone | 48% |
| Earthquake-induced landslide zone | 3% |
Dam inundation, aircraft noise & air quality
annual average fine-particle (PM2.5) concentration across its census tracts is 8.7 μg/m³, and its composite pollution burden ranks around the 18th percentile statewide.
| Annual PM2.5 (tract average) | 8.7 μg/m³ |
| Pollution burden percentile (statewide) | ~18 |
Frequently asked questions
- Is San Miguel in a wildfire hazard severity zone?
- CAL FIRE's current Fire Hazard Severity Zone maps do not designate any zones within San Miguel. Individual properties near the boundary can still fall inside a neighboring zone — check the exact address on the map.
- Is San Miguel in a FEMA flood zone?
- 6% of San Miguel lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 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 Miguel?
- The nearest mapped fault, the Mount Diablo thrust fault, is about 0.9 mi (1.4 km) from the center of San Miguel. 48% of its area is in a state-designated liquefaction zone of required investigation. 3% is in an earthquake-induced landslide zone.
- How do I check a specific address in San Miguel?
- Use the free sitelume interactive map at https://sitelume.com — search any San Miguel address to see which mapped zones it falls in, layer by layer.
Nearby in Contra Costa 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.