Jefferson County, OK's soil, for a septic absorption field
Very limited
Soil across 60.5% of Jefferson County, OK rates "Very limited" in USDA's septic-absorption-field interpretation. Practically, that rules out a simple gravity system for most of the county - 60.5% of it sits in USDA's most-constrained bucket. Jefferson County, OK is 758.956 square miles with a population of 5,374.
What Jefferson County's reading doesn't cover
This is a countywide, area-weighted figure across every soil survey map unit in Jefferson County, OK - 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 Jefferson County will actually do.
What a system would cost here
With 60.5% of Jefferson 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.
Jefferson County's rank among Oklahoma counties
Nationally, Jefferson County, OK is the 2,718-most-constrained of 3,058 rated counties for septic soil. Within Oklahoma alone it ranks 73 of 77.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems