Lafayette County's SSURGO septic rating
Very limited
USDA puts Lafayette County, MO at "Very limited" for septic absorption fields, the dominant reading across 84.5% of the county's soil. 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. The county spans 628.284 square miles, home to 33,511 people.
What this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in Lafayette County, MO - never a reading for one specific parcel. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Lafayette County: conventional vs. engineered cost
84.5% of Lafayette 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.
Lafayette County's rank among Missouri counties
Among the 3,058 rated counties on this site, Lafayette County, MO ranks 1,733 most-constrained nationally, and 91 of 114 within Missouri.
Before you act on this
How this rating is built, and its real limits · Conventional vs. engineered septic systems