Pittsburg County, OK's soil, for a septic absorption field
Very limited
In Pittsburg County, OK, 94% of the surveyed land carries a "Very limited" rating for a standard septic drain field. Practically, that rules out a simple gravity system for most of the county - 94% of it sits in USDA's most-constrained bucket. Pittsburg County, OK is 1,305.512 square miles with a population of 43,395.
What Pittsburg County's reading doesn't cover
Two lots a mile apart in Pittsburg 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 Pittsburg County will actually do.
What a system would cost here
With 94% of Pittsburg 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 Pittsburg County, OK compares
Nationally, Pittsburg County, OK is the 786-most-constrained of 3,058 rated counties for septic soil. Within Oklahoma alone it ranks 8 of 77.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems