Septic soil in Lafayette County, AR, by the numbers
Very limited
87.8% of Lafayette County, AR's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 87.8% of the county. Lafayette County, AR is 529.472 square miles with a population of 6,015.
What Lafayette County's reading doesn't cover
Lafayette 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 Lafayette County will actually do.
What a system would cost here
With 87.8% of Lafayette 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 Lafayette County, AR compares
Nationally, Lafayette County, AR is the 1,486-most-constrained of 3,058 rated counties for septic soil. Within Arkansas alone it ranks 54 of 75.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems