Septic suitability in Cheatham County, TN
Very limited
Cheatham County, TN's SSURGO dominant class comes back "Very limited", covering 80.6% 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. The county spans 302.498 square miles, home to 42,604 people.
What this number does and doesn't tell you
Two lots a mile apart in Cheatham County can carry different soil, even though they share one countywide rating. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Cheatham County: conventional vs. engineered cost
80.6% of Cheatham County carrying a "Very limited" reading changes the realistic budget here. 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, Cheatham County, TN ranks 2,012 most-constrained nationally, and 56 of 95 within Tennessee.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems