Bates County, MO: the USDA septic-suitability picture
Very limited
Bates County, MO: USDA's soil survey calls 99% of the county "Very limited" for a septic leach field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 99% of the county. The county spans 836.696 square miles, home to 16,394 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Bates 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.
Bates County: conventional vs. engineered cost
99% of Bates 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, Bates County, MO ranks 95 most-constrained nationally, and 16 of 114 within Missouri.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems