Septic soil in Graham County, KS, by the numbers
Somewhat limited
Soil across 54.4% of Graham County, KS rates "Somewhat limited" in USDA's septic-absorption-field interpretation. That's a middle reading: not the outright failure "very limited" soil produces, but not a clean pass either. Design changes often bridge the gap. Graham County covers 898.527 square miles and counts 2,370 residents.
This is a county figure, not a parcel figure
Two lots a mile apart in Graham County can carry different soil, even though they share one countywide rating. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Graham County.
System cost, conventional vs. engineered
Given Graham County's rating, plan for the engineered-system range rather than the conventional one. 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, Graham County, KS is the 2,931-most-constrained of 3,058 rated counties for septic soil. Within Kansas alone it ranks 95 of 105.
Related guides
How this rating is built, and its real limits · How a percolation test actually works