Septic soil in Calhoun County, MS, by the numbers

Very limited

98.7% of Calhoun County, MS's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. Calhoun County covers 586.573 square miles and counts 12,754 residents.

This is a county figure, not a parcel figure

USDA's survey covers the whole of Calhoun County, MS 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 Calhoun County.

System cost, conventional vs. engineered

Given Calhoun 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.

Calhoun County's rank among Mississippi counties

Nationally, Calhoun County, MS is the 135-most-constrained of 3,058 rated counties for septic soil. Within Mississippi alone it ranks 7 of 82.

Before you act on this

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