What Buchanan County, MO's soil rates for a septic system
Very limited
56.1% of Buchanan County, MO's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption 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. Buchanan County, MO is 408.249 square miles with a population of 83,574.
What Buchanan County's reading doesn't cover
This is a countywide, area-weighted figure across every soil survey map unit in Buchanan County, MO - never a reading for one specific parcel. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Buchanan County will actually do.
What a system would cost here
With 56.1% of Buchanan 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 Buchanan County, MO compares
Nationally, Buchanan County, MO is the 2,800-most-constrained of 3,058 rated counties for septic soil. Within Missouri alone it ranks 114 of 114.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems