Sinkhole risk in Calaveras County, CA: No soluble rock mapped

No soluble rock mapped

No soluble bedrock mapped.

On soluble rock: under 1%
At or near the surface: under 1%
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.

That works out to roughly 7 of Calaveras County's 1,020 square miles on soluble rock, 7 of them with the rock at or near the surface. With about 46,505 residents (46 per square mile), much of the land is open, and the mapped rock may sit far from where people actually live. The figures come from 427 map points about 1.5 miles apart, so a pocket smaller than that can be missed or overstated.

Two things to read before deciding: how these percentages are measured, and the warning signs that apply anywhere.

Counties around Calaveras County

The nearest county rated sinkhole country is Emery County, UT, about 534 miles east. 6 of the 6 closest counties land in the same band, so this is a regional pattern rather than a local quirk.

Amador County, CA 18 mi north · 0% at surface
Tuolumne County, CA 34 mi east · under 1% at surface
El Dorado County, CA 41 mi north · 0% at surface
San Joaquin County, CA 43 mi southwest · 0% at surface
Sacramento County, CA 46 mi northwest · 0% at surface
Stanislaus County, CA 50 mi southwest · 0% at surface

What Calaveras County is built on

The largest mapped soluble unit here is the Limestone of probable Paleozoic or Mesozoic age (limestone), Paleozoic to Mesozoic in age, covering about under 1% of the county.

Against the rest of California

Calaveras County ranks 21 of 58 in California for soluble rock at the surface, and sits above 54% of US counties on that measure.