Logan County's SSURGO septic rating
Very limited
Logan County, CO's SSURGO dominant class comes back "Very limited", covering 57.8% of the county. 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. The county spans 1,838.599 square miles, home to 20,755 people.
What this number does and doesn't tell you
Nothing about Logan County, CO'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.
Logan County: conventional vs. engineered cost
57.8% of Logan 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, Logan County, CO ranks 2,768 most-constrained nationally, and 50 of 63 within Colorado.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems