Septic soil in Camden County, MO, by the numbers
Very limited
Soil across 71.4% of Camden County, MO rates "Very limited" in USDA's septic-absorption-field interpretation. Practically, that rules out a simple gravity system for most of the county - 71.4% of it sits in USDA's most-constrained bucket. Camden County, MO is 655.937 square miles with a population of 44,135.
What Camden County's reading doesn't cover
USDA's survey covers the whole of Camden County, MO at once, not any single address. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Camden County will actually do.
What a system would cost here
With 71.4% of Camden 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.
Camden County's rank among Missouri counties
Nationally, Camden County, MO is the 2,425-most-constrained of 3,058 rated counties for septic soil. Within Missouri alone it ranks 108 of 114.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems