Los Altos Hills, CA— fire, flood & earthquake hazard information
Los Altos Hills is a city in Santa Clara County in the San Francisco Bay Area, covering about 9.1 square miles. This page summarizes what official government maps show for Los Altos Hills: 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 Los Altos Hills’s area that falls inside each mapped zone.
View Los Altos Hills on the interactive map → to check any specific address, free.
Wildfire hazard severity zones
Per CAL FIRE's Fire Hazard Severity Zone maps, less than 1% is in a High zone, less than 1% is in a Moderate zone. The remainder of its area is outside currently designated zones.
| High severity zone | less than 1% |
| Moderate severity zone | less than 1% |
FEMA flood zones
2% of Los Altos Hills lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 89% 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) | 89% |
Earthquake faults & seismic zones
The nearest mapped fault, the Monte Vista-Shannon fault zone, is about 0.1 mi (0.2 km) from the center of Los Altos Hills. 2 named fault traces in the USGS Quaternary fault database cross its boundary. 6% of its area is in a state-designated liquefaction zone of required investigation. 20% is in an earthquake-induced landslide zone.
| Nearest mapped fault | Monte Vista-Shannon fault zone — 0.1 mi (0.2 km) |
| Named fault traces crossing boundary | 2 |
| Liquefaction zone | 6% |
| Earthquake-induced landslide zone | 20% |
Dam inundation, aircraft noise & air quality
annual average fine-particle (PM2.5) concentration across its census tracts is 7.8 μg/m³, and its composite pollution burden ranks around the 30th percentile statewide.
| Annual PM2.5 (tract average) | 7.8 μg/m³ |
| Pollution burden percentile (statewide) | ~30 |
Frequently asked questions
- Is Los Altos Hills in a wildfire hazard severity zone?
- Per CAL FIRE's Fire Hazard Severity Zone maps, less than 1% is in a High zone, less than 1% is in a Moderate zone. The remainder of its area is outside currently designated zones.
- Is Los Altos Hills in a FEMA flood zone?
- 2% of Los Altos Hills lies within a FEMA Special Flood Hazard Area (1% annual chance, zones A/AE/AH/AO); 89% 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 Los Altos Hills?
- The nearest mapped fault, the Monte Vista-Shannon fault zone, is about 0.1 mi (0.2 km) from the center of Los Altos Hills. 2 named fault traces in the USGS Quaternary fault database cross its boundary. 6% of its area is in a state-designated liquefaction zone of required investigation. 20% is in an earthquake-induced landslide zone.
- How do I check a specific address in Los Altos Hills?
- Use the free sitelume interactive map at https://sitelume.com — search any Los Altos Hills address to see which mapped zones it falls in, layer by layer.
Nearby in Santa Clara 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.