What Logan County, WV's soil rates for a septic system
Very limited
95.3% of Logan County, WV's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. Practically, that rules out a simple gravity system for most of the county - 95.3% of it sits in USDA's most-constrained bucket. Logan County, WV is 452.904 square miles with a population of 30,560.
What Logan County's reading doesn't cover
USDA's survey covers the whole of Logan County, WV 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 Logan County will actually do.
What a system would cost here
With 95.3% of Logan 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 Logan County, WV compares
Nationally, Logan County, WV is the 634-most-constrained of 3,058 rated counties for septic soil. Within West Virginia alone it ranks 27 of 55.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems