Shelby County's SSURGO septic rating

Very limited

Shelby County, MO: USDA's soil survey calls 99.5% of the county "Very limited" for a septic leach field. Practically, that rules out a simple gravity system for most of the county - 99.5% of it sits in USDA's most-constrained bucket. For scale: 500.863 square miles and 5,926 people call Shelby County home.

Before you rely on this for one lot

Two lots a mile apart in Shelby County can carry different soil, even though they share one countywide rating. 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 Shelby County, MO

Shelby 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.

Shelby County's rank among Missouri counties

Among the 3,058 rated counties on this site, Shelby County, MO ranks 30 most-constrained nationally, and 4 of 114 within Missouri.

Further reading

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