Carlisle County, KY: the USDA septic-suitability picture
Very limited
Carlisle County, KY: USDA's soil survey calls 92% of the county "Very limited" for a septic leach field. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 92% of Carlisle County's land. The county spans 189.463 square miles, home to 4,777 people.
What this number does and doesn't tell you
Two lots a mile apart in Carlisle 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.
Carlisle County: conventional vs. engineered cost
92% of Carlisle 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.
Where this sits nationally
Among the 3,058 rated counties on this site, Carlisle County, KY ranks 1,050 most-constrained nationally, and 53 of 119 within Kentucky.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems