Septic suitability in Haakon County, SD
Very limited
Haakon County, SD's SSURGO dominant class comes back "Very limited", covering 95.1% of the county. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 95.1% of Haakon County's land. The county spans 1,810.541 square miles, home to 1,834 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Haakon County, SD at once, not any single address. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Haakon County: conventional vs. engineered cost
95.1% of Haakon County carrying a "Very limited" reading changes the realistic budget here. Conventional systems run $3,000-$8,000 where they pass; where they don't, engineered alternatives (mound or aerobic treatment, whichever the health department requires) run $10,000-$40,000 - budget toward the higher figure until a perc test says otherwise.
Where this sits nationally
Among the 3,058 rated counties on this site, Haakon County, SD ranks 665 most-constrained nationally, and 8 of 66 within South Dakota.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems