Foard County, TX's soil, for a septic absorption field
Very limited
95% of Foard County, TX'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% of it sits in USDA's most-constrained bucket. Foard County, TX is 704.395 square miles with a population of 1,053.
What Foard County's reading doesn't cover
This is a countywide, area-weighted figure across every soil survey map unit in Foard County, TX - 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 Foard County will actually do.
What a system would cost here
With 95% of Foard 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.
Where this sits nationally
Nationally, Foard County, TX is the 673-most-constrained of 3,058 rated counties for septic soil. Within Texas alone it ranks 45 of 253.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems