Septic soil in Otoe County, NE, by the numbers
Very limited
94.4% of Otoe County, NE's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 94.4% of the county. Otoe County, NE is 615.618 square miles with a population of 16,591.
What Otoe County's reading doesn't cover
Two lots a mile apart in Otoe 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 Otoe County will actually do.
What a system would cost here
With 94.4% of Otoe 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.
Otoe County's rank among Nebraska counties
Nationally, Otoe County, NE is the 731-most-constrained of 3,058 rated counties for septic soil. Within Nebraska alone it ranks 20 of 93.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems