Septic soil in Hughes County, OK, by the numbers
Very limited
In Hughes County, OK, 86.4% of the surveyed land carries a "Very limited" rating for a standard septic drain field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 86.4% of the county. Hughes County, OK is 804.473 square miles with a population of 13,371.
What Hughes County's reading doesn't cover
Two lots a mile apart in Hughes County can carry different soil, even though they share one countywide rating. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Hughes County will actually do.
What a system would cost here
With 86.4% of Hughes 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.
Hughes County's rank among Oklahoma counties
Nationally, Hughes County, OK is the 1,582-most-constrained of 3,058 rated counties for septic soil. Within Oklahoma alone it ranks 30 of 77.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems