Septic suitability in Cass County, NE
Very limited
Cass County, NE's SSURGO dominant class comes back "Very limited", covering 90.5% of the county. Practically, that rules out a simple gravity system for most of the county - 90.5% of it sits in USDA's most-constrained bucket. For scale: 556.911 square miles and 27,492 people call Cass County home.
Before you rely on this for one lot
USDA's survey covers the whole of Cass County, NE at once, not any single address. The real answer for one lot is still a site-specific perc test, running about $750-$1,850 (typically near $1,300).
Budgeting for a system in Cass County, NE
Cass County's soil reading pushes the likely outcome toward an engineered system rather than a conventional one. 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, Cass County, NE ranks 1,213 most-constrained nationally, and 26 of 93 within Nebraska.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems