Sinkhole risk in Marin 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 this means before you buy

No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.

Across 520 square miles, under one square mile of Marin County maps onto soluble rock. With about 256,400 residents (493 per square mile), homes are spread across towns and farmland, and a mapped unit may or may not reach the developed parts. The figures come from 516 map points about 1.0 miles apart, so a pocket smaller than that can be missed or overstated.

Worth reading for this county: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Marin County

The nearest county rated sinkhole country is Emery County, UT, about 653 miles east. 4 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

San Francisco County, CA 27 mi southwest · 0% at surface
Sonoma County, CA 34 mi north · 0% at surface
Napa County, CA 39 mi northeast · 2% at surface
Contra Costa County, CA 44 mi east · 0% at surface
Solano County, CA 46 mi east · 0% at surface
San Mateo County, CA 49 mi southeast · 1% at surface

Against the rest of California

Marin County ranks 39 of 58 in California for soluble rock at the surface, and sits above 0% of US counties on that measure.