Deschutes County, OR: the USDA septic-suitability picture
Very limited
Deschutes County, OR's SSURGO dominant class comes back "Very limited", covering 79.3% of the county. That reading means a conventional system is a poor bet here - 79.3% of Deschutes County lands in the strictest "very limited" bucket USDA uses. The county spans 3,017.61 square miles, home to 211,535 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Deschutes 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.
Deschutes County: conventional vs. engineered cost
79.3% of Deschutes 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, Deschutes County, OR ranks 2,073 most-constrained nationally, and 31 of 36 within Oregon.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems