Yamhill County's SSURGO septic rating

Very limited

USDA puts Yamhill County, OR at "Very limited" for septic absorption fields, the dominant reading across 97% of the county's soil. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 97% of the county. The county spans 715.938 square miles, home to 110,886 people.

What this number does and doesn't tell you

USDA's survey covers the whole of Yamhill County, OR at once, not any single address. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.

Yamhill County: conventional vs. engineered cost

97% of Yamhill County carrying a "Very limited" reading changes the realistic budget here. 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.

Where this sits nationally

Among the 3,058 rated counties on this site, Yamhill County, OR ranks 372 most-constrained nationally, and 7 of 36 within Oregon.

Before you act on this

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