Septic suitability in Kittitas County, WA
Very limited
Kittitas County, WA: USDA's soil survey calls 94.8% of the county "Very limited" for a septic leach field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 94.8% of the county. The county spans 2,297.291 square miles, home to 48,172 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Kittitas County, WA 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.
Kittitas County: conventional vs. engineered cost
94.8% of Kittitas 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, Kittitas County, WA ranks 687 most-constrained nationally, and 12 of 39 within Washington.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems