Disclaimer

sitelume aggregates publicly available environmental and hazard data for Bay Area properties. The information shown is provided for general informational purposes only and is not a substitute for an official report, professional inspection, or legal advice.

Not an official report

Nothing on this site constitutes a Natural Hazard Disclosure (NHD) report, a flood-zone determination, an insurance underwriting decision, a title report, or a real-estate disclosure required by California Civil Code. Buyers, sellers, lenders, insurers, and agents must obtain authoritative reports from licensed providers.

No warranty of accuracy or completeness

We compile data from federal, state, and local public agencies and open-data providers. Upstream datasets have varying publication cadences, vintages, and known limitations. Coverage gaps, modeling assumptions, and reporting lags all affect what you see. We make no representation that information shown is current, accurate, or complete for any particular property.

Limits of specific layers

Airport noise contoursreflect each airport’s most recently published noise study and may pre-date current flight operations by several years.
Flight-track density is a count of overflights derived from aircraft that broadcast their position — not a modeled noise level. Aircraft that do not broadcast (some general aviation, military) are not included.
Air quality live readings come from regulatory monitoring stations that may be several miles from any given property; we do not interpolate the AQI to an address.
Live freeway traffic reflects segment speeds relative to typical-time-of-day baselines, not legal speed limits.
Earthquake fault, Alquist-Priolo, liquefaction, and landslide zones follow published hazard-zone mapping; absence of a mapped feature does not imply zero risk. Alquist-Priolo zones are the regulatory ~500 ft buffers around active fault traces under PRC § 2622 — distinct from the USGS fault lines used to compute distance-to-nearest-fault.
Dam-failure inundationpolygons show the maximum extent of flooding from a hypothetical dam failure — not a probability of failure occurring. Coverage is limited to dams classified Significant, High, or Extremely High hazard, and reflects DSOD-approved maps as of the dataset’s publication date.

Data sources

The information shown is compiled from the following sources:

Fire hazard zones — CAL FIRE OSFM
Flood zones — FEMA NFHL
Dam-failure inundation — California Department of Water Resources, Division of Safety of Dams (DSOD), Approved Inundation Boundaries
Liquefaction zones — California Geological Survey (CGS) Seismic Hazard Zones
Earthquake-induced landslide zones — California Geological Survey (CGS) Seismic Hazard Zones
Earthquake faults — USGS Quaternary Faults
Alquist-Priolo Earthquake Fault Zones — California Geological Survey (CGS) regulatory zones
Airport noise contours — county Airport Land Use Commissions (Santa Clara, San Mateo/SFIA, Alameda)
Flight-track density — OpenSky Network (non-commercial use)
Live freeway traffic — MTC 511 SF Bay; baseline volumes (AADT) from Caltrans
Live air quality — OpenAQ v3 (AirNow + CARB)

Use at your own risk

Decisions involving the purchase, sale, financing, insurance, or habitability of real property must rely on official reports from qualified professionals and authoritative agencies. sitelume and its operators accept no liability for actions taken in reliance on information shown here.

Last updated: 2026-05-27.