Tillamook County, OR: the USDA septic-suitability picture

Very limited

Tillamook County, OR's SSURGO dominant class comes back "Very limited", covering 96.1% of the county. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. For scale: 1,103.185 square miles and 27,264 people call Tillamook County home.

Before you rely on this for one lot

USDA's survey covers the whole of Tillamook County, OR at once, not any single address. The real answer for one lot is still a site-specific perc test, running about $750-$1,850 (typically near $1,300).

Budgeting for a system in Tillamook County, OR

Tillamook County's soil reading pushes the likely outcome toward an engineered system rather than a conventional one. 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.

Tillamook County's rank among Oregon counties

Among the 3,058 rated counties on this site, Tillamook County, OR ranks 513 most-constrained nationally, and 10 of 36 within Oregon.

Before you act on this

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