What Wilkinson County, MS's soil rates for a septic system

Very limited

88.2% of Wilkinson County, MS'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 - 88.2% of it sits in USDA's most-constrained bucket. Wilkinson County covers 678.012 square miles and counts 7,820 residents.

This is a county figure, not a parcel figure

USDA's survey covers the whole of Wilkinson County, MS at once, not any single address. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Wilkinson County.

System cost, conventional vs. engineered

Given Wilkinson 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, Wilkinson County, MS is the 1,453-most-constrained of 3,058 rated counties for septic soil. Within Mississippi alone it ranks 55 of 82.

Further reading

How this rating is built, and its real limits · Conventional vs. engineered septic systems