Houston County, TN's soil, for a septic absorption field
Very limited
69.5% of Houston 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 - 69.5% of it sits in USDA's most-constrained bucket. Houston County, TN is 200.294 square miles with a population of 8,538.
What Houston County's reading doesn't cover
Houston 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 Houston County will actually do.
What a system would cost here
With 69.5% of Houston 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.
Houston County's rank among Tennessee counties
Nationally, Houston County, TN is the 2,482-most-constrained of 3,058 rated counties for septic soil. Within Tennessee alone it ranks 79 of 95.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems