Sinkhole risk in San Francisco County, CA: No soluble rock mapped
No soluble rock mapped
No soluble bedrock mapped.
- On soluble rock
- 0%
- At or near the surface
- 0%
- Buried under cover
- 0%
What to do about a house in San Francisco County
No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.
Across 47 square miles, under one square mile of San Francisco County maps onto soluble rock. With about 827,526 residents (17,726 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 310 map points about 0.4 miles apart, so a pocket smaller than that can be missed or overstated.
Read next: how these percentages are measured, and the warning signs that apply anywhere.
Counties around San Francisco County
The nearest county rated sinkhole country is Emery County, UT, about 672 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.
- Marin County, CA 27 mi northeast · 0% at surface
- San Mateo County, CA 42 mi southeast · 1% at surface
- Sonoma County, CA 55 mi north · 0% at surface
- Contra Costa County, CA 60 mi east · 0% at surface
- Alameda County, CA 61 mi east · 0% at surface
- Napa County, CA 66 mi northeast · 2% at surface
Against the rest of California
San Francisco County ranks 50 of 58 in California for soluble rock at the surface, and sits above 0% of US counties on that measure.
- Trinity County 25%
- Inyo County 17%
- Ventura County 9%
- Shasta County 9%
- Siskiyou County 9%