Septic suitability in Hickory County, MO
Very limited
USDA puts Hickory County, MO at "Very limited" for septic absorption fields, the dominant reading across 92.8% of the county's soil. Practically, that rules out a simple gravity system for most of the county - 92.8% of it sits in USDA's most-constrained bucket. The county spans 398.808 square miles, home to 8,766 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Hickory County, MO at once, not any single address. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Hickory County: conventional vs. engineered cost
92.8% of Hickory County carrying a "Very limited" reading changes the realistic budget here. Conventional systems run $3,000-$8,000 where they pass; where they don't, engineered alternatives (mound or aerobic treatment, whichever the health department requires) run $10,000-$40,000 - budget toward the higher figure until a perc test says otherwise.
Where this sits nationally
Among the 3,058 rated counties on this site, Hickory County, MO ranks 956 most-constrained nationally, and 64 of 114 within Missouri.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems