Clarke County, MS's soil, for a septic absorption field

Very limited

Soil across 89.3% of Clarke County, MS rates "Very limited" in USDA's septic-absorption-field interpretation. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 89.3% of Clarke County's land. Clarke County covers 691.576 square miles and counts 15,155 residents.

This is a county figure, not a parcel figure

Two lots a mile apart in Clarke County can carry different soil, even though they share one countywide rating. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Clarke County.

System cost, conventional vs. engineered

Given Clarke 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, Clarke County, MS is the 1,346-most-constrained of 3,058 rated counties for septic soil. Within Mississippi alone it ranks 53 of 82.

Further reading

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