Cheshire County's SSURGO septic rating
Very limited
USDA puts Cheshire County, NH at "Very limited" for septic absorption fields, the dominant reading across 81.8% of the county's soil. Practically, that rules out a simple gravity system for most of the county - 81.8% of it sits in USDA's most-constrained bucket. For scale: 706.725 square miles and 78,078 people call Cheshire County home.
Before you rely on this for one lot
Two lots a mile apart in Cheshire County can carry different soil, even though they share one countywide rating. The real answer for one lot is still a site-specific perc test, running about $750-$1,850 (typically near $1,300).
Budgeting for a system in Cheshire County, NH
Cheshire County's soil reading pushes the likely outcome toward an engineered system rather than a conventional one. 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.
Cheshire County's rank among New Hampshire counties
Among the 3,058 rated counties on this site, Cheshire County, NH ranks 1,939 most-constrained nationally, and 10 of 10 within New Hampshire.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems