Coos County, NH's soil, for a septic absorption field

Very limited

Soil across 92.6% of Coos County, NH rates "Very limited" in USDA's septic-absorption-field interpretation. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 92.6% of the county. Coos County, NH is 1,794.574 square miles with a population of 31,094.

What Coos County's reading doesn't cover

Two lots a mile apart in Coos County can carry different soil, even though they share one countywide rating. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Coos County will actually do.

What a system would cost here

With 92.6% of Coos County rating "Very limited", a standard gravity system is not a safe assumption here. The engineered-system range, $10,000-$40,000 (mound or aerobic treatment), is the more realistic number to plan around, against $3,000-$8,000 for a conventional system on the rare lot that passes.

How Coos County, NH compares

Nationally, Coos County, NH is the 973-most-constrained of 3,058 rated counties for septic soil. Within New Hampshire alone it ranks 1 of 10.

Before you act on this

How this rating is built, and its real limits · Conventional vs. engineered septic systems