San Ramon, CA— fire, flood & earthquake hazard information
San Ramon is a city in Contra Costa County in the San Francisco Bay Area, covering about 20.1 square miles. This page summarizes what official government maps show for San Ramon: 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 Ramon’s area that falls inside each mapped zone.
View San Ramon on the interactive map → to check any specific address, free.
Wildfire hazard severity zones
Per CAL FIRE's Fire Hazard Severity Zone maps, 5% is in a High zone, 25% is in a Moderate zone. The remainder of its area is outside currently designated zones.
| High severity zone | 5% |
| Moderate severity zone | 25% |
FEMA flood zones
2% of San Ramon 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) | 2% |
| 0.2% annual chance (500-yr) | less than 1% |
Earthquake faults & seismic zones
The nearest mapped fault, the Pleasanton fault, is about 0.4 mi (0.6 km) from the center of San Ramon. 4 named fault traces in the USGS Quaternary fault database cross its boundary. 36% of its area is in a state-designated liquefaction zone of required investigation. 9% is in an earthquake-induced landslide zone. 5% falls within an Alquist-Priolo earthquake fault zone, where new construction requires a fault study.
| Nearest mapped fault | Pleasanton fault — 0.4 mi (0.6 km) |
| Named fault traces crossing boundary | 4 |
| Liquefaction zone | 36% |
| Earthquake-induced landslide zone | 9% |
| Alquist-Priolo fault zone | 5% |
Dam inundation, aircraft noise & air quality
annual average fine-particle (PM2.5) concentration across its census tracts is 8.5 μg/m³, and its composite pollution burden ranks around the 7th percentile statewide.
| Annual PM2.5 (tract average) | 8.5 μg/m³ |
| Pollution burden percentile (statewide) | ~7 |
Frequently asked questions
- Is San Ramon in a wildfire hazard severity zone?
- Per CAL FIRE's Fire Hazard Severity Zone maps, 5% is in a High zone, 25% is in a Moderate zone. The remainder of its area is outside currently designated zones.
- Is San Ramon in a FEMA flood zone?
- 2% of San Ramon 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 Ramon?
- The nearest mapped fault, the Pleasanton fault, is about 0.4 mi (0.6 km) from the center of San Ramon. 4 named fault traces in the USGS Quaternary fault database cross its boundary. 36% of its area is in a state-designated liquefaction zone of required investigation. 9% is in an earthquake-induced landslide zone. 5% falls within an Alquist-Priolo earthquake fault zone, where new construction requires a fault study.
- How do I check a specific address in San Ramon?
- Use the free sitelume interactive map at https://sitelume.com — search any San Ramon 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.