Washington County's SSURGO septic rating

Very limited

Washington County, ID's SSURGO dominant class comes back "Very limited", covering 92.9% of the county. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 92.9% of the county. For scale: 1,452.855 square miles and 11,539 people call Washington County home.

Before you rely on this for one lot

Two lots a mile apart in Washington 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 Washington County, ID

Washington 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.

Washington County's rank among Idaho counties

Among the 3,058 rated counties on this site, Washington County, ID ranks 944 most-constrained nationally, and 8 of 44 within Idaho.

Related guides

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