What Greene County, TN's soil rates for a septic system
Very limited
Soil across 79.2% of Greene County, TN rates "Very limited" in USDA's septic-absorption-field interpretation. Practically, that rules out a simple gravity system for most of the county - 79.2% of it sits in USDA's most-constrained bucket. Greene County covers 622.169 square miles and counts 73,398 residents.
This is a county figure, not a parcel figure
This is a countywide, area-weighted figure across every soil survey map unit in Greene County, TN - never a reading for one specific parcel. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Greene County.
System cost, conventional vs. engineered
Given Greene County's rating, plan for the engineered-system range rather than the conventional one. 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.
Where this sits nationally
Nationally, Greene County, TN is the 2,078-most-constrained of 3,058 rated counties for septic soil. Within Tennessee alone it ranks 58 of 95.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems