Septic suitability in Park County, MT
Very limited
Park County, MT: USDA's soil survey calls 81.4% of the county "Very limited" for a septic leach field. 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 2,802.479 square miles, home to 18,074 people.
What this number does and doesn't tell you
Nothing about Park County, MT'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.
Park County: conventional vs. engineered cost
81.4% of Park 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.
Park County's rank among Montana counties
Among the 3,058 rated counties on this site, Park County, MT ranks 1,972 most-constrained nationally, and 27 of 54 within Montana.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems