Septic suitability in Perkins County, SD
Very limited
USDA puts Perkins County, SD at "Very limited" for septic absorption fields, the dominant reading across 88.7% of the county's soil. Practically, that rules out a simple gravity system for most of the county - 88.7% of it sits in USDA's most-constrained bucket. The county spans 2,870.46 square miles, home to 2,832 people.
What this number does and doesn't tell you
Nothing about Perkins County, SD's SSURGO figure applies to a specific address - it's a county-wide average. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Perkins County: conventional vs. engineered cost
88.7% of Perkins 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, Perkins County, SD ranks 1,402 most-constrained nationally, and 32 of 66 within South Dakota.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems