Septic soil in McDonald County, MO, by the numbers

Very limited

In McDonald County, MO, 78.6% of the surveyed land carries a "Very limited" rating for a standard septic drain field. 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. McDonald County covers 539.445 square miles and counts 24,054 residents.

This is a county figure, not a parcel figure

McDonald County's rating is an average across the whole county, not a promise about any one lot inside it. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in McDonald County.

System cost, conventional vs. engineered

Given McDonald 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, McDonald County, MO is the 2,112-most-constrained of 3,058 rated counties for septic soil. Within Missouri alone it ranks 103 of 114.

Further reading

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