Cumberland County, TN: the USDA septic-suitability picture
Very limited
Cumberland County, TN's SSURGO dominant class comes back "Very limited", covering 91.9% of the county. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. For scale: 681.309 square miles and 65,618 people call Cumberland County home.
Before you rely on this for one lot
USDA's survey covers the whole of Cumberland County, TN 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 Cumberland County, TN
Cumberland 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.
How Cumberland County, TN compares
Among the 3,058 rated counties on this site, Cumberland County, TN ranks 1,054 most-constrained nationally, and 17 of 95 within Tennessee.
Before you act on this
How this rating is built, and its real limits · Conventional vs. engineered septic systems