Septic suitability in Marion County, OR

Very limited

USDA puts Marion County, OR at "Very limited" for septic absorption fields, the dominant reading across 93% of the county's soil. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 93% of the county. For scale: 1,180.84 square miles and 352,867 people call Marion County home.

Before you rely on this for one lot

Nothing about Marion County, OR's SSURGO figure applies to a specific address - it's a county-wide average. 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 Marion County, OR

Marion 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.

Where this sits nationally

Among the 3,058 rated counties on this site, Marion County, OR ranks 920 most-constrained nationally, and 22 of 36 within Oregon.

Further reading

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