Septic soil in Modoc County, CA, by the numbers

Very limited

81% of Modoc County, CA's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. That reading means a conventional system is a poor bet here - 81% of Modoc County lands in the strictest "very limited" bucket USDA uses. Modoc County covers 3,948.233 square miles and counts 8,491 residents.

This is a county figure, not a parcel figure

USDA's survey covers the whole of Modoc County, CA at once, not any single address. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Modoc County.

System cost, conventional vs. engineered

Given Modoc County's rating, plan for the engineered-system range rather than the conventional one. The engineered-system range, $10,000-$40,000 (mound or aerobic treatment), is the more realistic number to plan around, against $3,000-$8,000 for a conventional system on the rare lot that passes.

Modoc County's rank among California counties

Nationally, Modoc County, CA is the 1,991-most-constrained of 3,058 rated counties for septic soil. Within California alone it ranks 50 of 57.

Before you act on this

How this rating is built, and its real limits · Conventional vs. engineered septic systems