Graves County, KY's soil, for a septic absorption field
Very limited
Soil across 80% of Graves County, KY rates "Very limited" in USDA's septic-absorption-field interpretation. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 80% of the county. Graves County, KY is 551.757 square miles with a population of 36,821.
What Graves County's reading doesn't cover
Graves County's rating is an average across the whole county, not a promise about any one lot inside it. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Graves County will actually do.
What a system would cost here
With 80% of Graves 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.
Where this sits nationally
Nationally, Graves County, KY is the 2,041-most-constrained of 3,058 rated counties for septic soil. Within Kentucky alone it ranks 89 of 119.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems