Septic suitability in Franklin County, MO

Very limited

USDA puts Franklin County, MO at "Very limited" for septic absorption fields, the dominant reading across 95.4% of the county's soil. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 95.4% of the county. For scale: 922.491 square miles and 107,256 people call Franklin County home.

Before you rely on this for one lot

USDA's survey covers the whole of Franklin County, MO 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 Franklin County, MO

Franklin 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.

Franklin County's rank among Missouri counties

Among the 3,058 rated counties on this site, Franklin County, MO ranks 608 most-constrained nationally, and 46 of 114 within Missouri.

Before you act on this

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