What Whitley County, KY's soil rates for a septic system
Very limited
95.6% of Whitley County, KY'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. Whitley County, KY is 437.921 square miles with a population of 37,233.
What Whitley County's reading doesn't cover
USDA's survey covers the whole of Whitley County, KY at once, not any single address. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Whitley County will actually do.
What a system would cost here
With 95.6% of Whitley County rating "Very limited", a standard gravity system is not a safe assumption here. 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.
Whitley County's rank among Kentucky counties
Nationally, Whitley County, KY is the 580-most-constrained of 3,058 rated counties for septic soil. Within Kentucky alone it ranks 24 of 119.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems