What Harrison County, MS's soil rates for a septic system
Very limited
Soil across 84.8% of Harrison County, MS rates "Very limited" in USDA's septic-absorption-field interpretation. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. Harrison County, MS is 573.65 square miles with a population of 213,730.
What Harrison County's reading doesn't cover
Two lots a mile apart in Harrison County can carry different soil, even though they share one countywide rating. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Harrison County will actually do.
What a system would cost here
With 84.8% of Harrison 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.
How Harrison County, MS compares
Nationally, Harrison County, MS is the 1,704-most-constrained of 3,058 rated counties for septic soil. Within Mississippi alone it ranks 62 of 82.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems