What Macon County, TN's soil rates for a septic system
Very limited
89.9% of Macon County, TN's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. Practically, that rules out a simple gravity system for most of the county - 89.9% of it sits in USDA's most-constrained bucket. Macon County, TN is 307.144 square miles with a population of 27,189.
What Macon County's reading doesn't cover
Macon County's rating is an average across the whole county, not a promise about any one lot inside it. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Macon County will actually do.
What a system would cost here
With 89.9% of Macon 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.
Macon County's rank among Tennessee counties
Nationally, Macon County, TN is the 1,277-most-constrained of 3,058 rated counties for septic soil. Within Tennessee alone it ranks 21 of 95.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems