What Pend Oreille County, WA's soil rates for a septic system
Very limited
92.8% of Pend Oreille County, WA's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. That reading means a conventional system is a poor bet here - 92.8% of Pend Oreille County lands in the strictest "very limited" bucket USDA uses. Pend Oreille County, WA is 1,400.245 square miles with a population of 14,332.
What Pend Oreille County's reading doesn't cover
This is a countywide, area-weighted figure across every soil survey map unit in Pend Oreille County, WA - never a reading for one specific parcel. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Pend Oreille County will actually do.
What a system would cost here
With 92.8% of Pend Oreille 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.
Where this sits nationally
Nationally, Pend Oreille County, WA is the 955-most-constrained of 3,058 rated counties for septic soil. Within Washington alone it ranks 16 of 39.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems