Septic soil in Appanoose County, IA, by the numbers
Very limited
Soil across 94.5% of Appanoose County, IA rates "Very limited" in USDA's septic-absorption-field interpretation. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 94.5% of the county. Appanoose County, IA is 497.299 square miles with a population of 12,106.
What Appanoose County's reading doesn't cover
Two lots a mile apart in Appanoose County can carry different soil, even though they share one countywide rating. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Appanoose County will actually do.
What a system would cost here
With 94.5% of Appanoose 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.
Where this sits nationally
Nationally, Appanoose County, IA is the 715-most-constrained of 3,058 rated counties for septic soil. Within Iowa alone it ranks 50 of 99.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems