What Polk County, MO's soil rates for a septic system

Very limited

91.7% of Polk County, MO's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. Practically, that rules out a simple gravity system for most of the county - 91.7% of it sits in USDA's most-constrained bucket. Polk County covers 635.527 square miles and counts 33,070 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in Polk County, MO - never a reading for one specific parcel. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Polk County.

System cost, conventional vs. engineered

Given Polk County's rating, plan for the engineered-system range rather than the conventional one. The engineered-system range, $10,000-$40,000 (mound or aerobic treatment), is the more realistic number to plan around, against $3,000-$8,000 for a conventional system on the rare lot that passes.

Polk County's rank among Missouri counties

Nationally, Polk County, MO is the 1,077-most-constrained of 3,058 rated counties for septic soil. Within Missouri alone it ranks 72 of 114.

Related guides

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