Septic soil in Wallowa County, OR, by the numbers

Very limited

Soil across 77.9% of Wallowa County, OR 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 77.9% of the county. Wallowa County, OR is 3,145.897 square miles with a population of 7,522.

What Wallowa County's reading doesn't cover

This is a countywide, area-weighted figure across every soil survey map unit in Wallowa County, OR - 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 Wallowa County will actually do.

What a system would cost here

With 77.9% of Wallowa 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.

Wallowa County's rank among Oregon counties

Nationally, Wallowa County, OR is the 2,144-most-constrained of 3,058 rated counties for septic soil. Within Oregon alone it ranks 34 of 36.

Further reading

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