Septic soil in Allen County, KY, by the numbers
Very limited
56.8% of Allen 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. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 56.8% of Allen County's land. Allen County, KY is 343.724 square miles with a population of 22,037.
What Allen County's reading doesn't cover
This is a countywide, area-weighted figure across every soil survey map unit in Allen County, KY - never a reading for one specific parcel. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Allen County will actually do.
What a system would cost here
With 56.8% of Allen 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.
How Allen County, KY compares
Nationally, Allen County, KY is the 2,785-most-constrained of 3,058 rated counties for septic soil. Within Kentucky alone it ranks 118 of 119.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems