Obion County, TN: the USDA septic-suitability picture
Very limited
USDA puts Obion County, TN at "Very limited" for septic absorption fields, the dominant reading across 83.4% of the county's soil. That reading means a conventional system is a poor bet here - 83.4% of Obion County lands in the strictest "very limited" bucket USDA uses. The county spans 544.851 square miles, home to 30,261 people.
What this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in Obion County, TN - never a reading for one specific parcel. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Obion County: conventional vs. engineered cost
83.4% of Obion 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.
How Obion County, TN compares
Among the 3,058 rated counties on this site, Obion County, TN ranks 1,831 most-constrained nationally, and 42 of 95 within Tennessee.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems