What Washington County, MO's soil rates for a septic system

Very limited

95.3% of Washington 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. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 95.3% of Washington County's land. Washington County, MO is 759.866 square miles with a population of 23,583.

What Washington County's reading doesn't cover

Washington County's rating is an average across the whole county, not a promise about any one lot inside it. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Washington County will actually do.

What a system would cost here

With 95.3% of Washington 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 Washington County, MO compares

Nationally, Washington County, MO is the 636-most-constrained of 3,058 rated counties for septic soil. Within Missouri alone it ranks 48 of 114.

Before you act on this

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