Clay County, KY: the USDA septic-suitability picture
Very limited
USDA puts Clay County, KY at "Very limited" for septic absorption fields, the dominant reading across 97.2% of the county's soil. That reading means a conventional system is a poor bet here - 97.2% of Clay County lands in the strictest "very limited" bucket USDA uses. The county spans 469.296 square miles, home to 19,592 people.
What this number does and doesn't tell you
Two lots a mile apart in Clay County can carry different soil, even though they share one countywide rating. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Clay County: conventional vs. engineered cost
97.2% of Clay County carrying a "Very limited" reading changes the realistic budget here. Conventional systems run $3,000-$8,000 where they pass; where they don't, engineered alternatives (mound or aerobic treatment, whichever the health department requires) run $10,000-$40,000 - budget toward the higher figure until a perc test says otherwise.
How Clay County, KY compares
Among the 3,058 rated counties on this site, Clay County, KY ranks 358 most-constrained nationally, and 13 of 119 within Kentucky.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems