Septic soil in Oglala Lakota County, SD, by the numbers

Very limited

84.9% of Oglala Lakota County, SD'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 84.9% of Oglala Lakota County's land. Oglala Lakota County, SD is 2,093.601 square miles with a population of 13,360.

What Oglala Lakota County's reading doesn't cover

Oglala Lakota 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 Oglala Lakota County will actually do.

What a system would cost here

With 84.9% of Oglala Lakota 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 Oglala Lakota County, SD compares

Nationally, Oglala Lakota County, SD is the 1,700-most-constrained of 3,058 rated counties for septic soil. Within South Dakota alone it ranks 41 of 66.

Further reading

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