Juniata County, PA: the USDA septic-suitability picture
Very limited
Juniata County, PA: USDA's soil survey calls 88.3% of the county "Very limited" for a septic leach field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 88.3% of the county. The county spans 391.391 square miles, home to 23,395 people.
What this number does and doesn't tell you
Juniata County's rating is an average across the whole county, not a promise about any one lot inside it. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Juniata County: conventional vs. engineered cost
88.3% of Juniata 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.
Juniata County's rank among Pennsylvania counties
Among the 3,058 rated counties on this site, Juniata County, PA ranks 1,439 most-constrained nationally, and 44 of 66 within Pennsylvania.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems