Rankin County, MS: the USDA septic-suitability picture
Very limited
USDA puts Rankin County, MS at "Very limited" for septic absorption fields, the dominant reading across 93.6% of the county's soil. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 93.6% of the county. The county spans 775.501 square miles, home to 160,573 people.
What this number does and doesn't tell you
Two lots a mile apart in Rankin 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.
Rankin County: conventional vs. engineered cost
93.6% of Rankin 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 Rankin County, MS compares
Among the 3,058 rated counties on this site, Rankin County, MS ranks 845 most-constrained nationally, and 34 of 82 within Mississippi.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems