South San Francisco, CA
How exposed is South San Francisco to wildfire?
Out of every US place USFS scores, South San Francisco lands at the 61st percentile for wildfire risk to structures — well above the national norm for wildfire risk — a figure built from its 17,744 buildings, not the land around them. (Source: USFS's Wildfire Risk to Communities methodology.)
Fire likelihood alone (USFS's burn-probability figure) ranks South San Francisco at the 59th national percentile — 1 points below its risk-to-structures score, a gap driven by how much is actually built there.
What "at risk" means for the buildings here
Indirect exposure is dominant in South San Francisco (49.6% of 17,744 buildings): far enough from burnable vegetation to avoid flame contact, close enough for wind-blown embers. Only 1.4% sit in the Direct zone. At 17,744 buildings, this is a substantial built environment, so the shares below describe a real population of structures, not a handful of edge cases.
South San Francisco against the rest of the country
South San Francisco ranks lower within California (19th percentile statewide) than its 61st national percentile suggests alone — a calmer spot in a state where wildfire risk generally runs high. Among the 31,521 US communities USFS scores, South San Francisco ranks 12,440 for wildfire risk (1 is highest) and 806 by building count (1 is largest). Within California alone, it ranks 1,278 of 1,570 places by risk. See the full county-by-county picture for California on its state page.
South San Francisco and the insurance market
Because South San Francisco is in California, a wildfire-hazard disclosure is legally required before a sale closes here — unusual nationally, since only these two states mandate it. The state's FAIR Plan alone carried 668,609 policies by the end of 2025. Full detail in the disclosure-law guide.
Hardening a home in South San Francisco
With ember exposure the dominant pattern in South San Francisco (49.6% Indirect), vent screens and roofing material tend to matter more than lot clearing alone. The home-hardening guide covers both.
More on how this number was built
South San Francisco's 61st-percentile score and its burn-probability figure both come from the same USFS workbook, documented in the methodology guide. For more on what indirect exposure implies beyond South San Francisco, see the exposure-zones guide.