Massac County, IL: the USDA septic-suitability picture

Very limited

USDA puts Massac County, IL at "Very limited" for septic absorption fields, the dominant reading across 93.9% of the county's soil. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 93.9% of Massac County's land. The county spans 237.152 square miles, home to 13,627 people.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Massac County, IL - 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.

Massac County: conventional vs. engineered cost

93.9% of Massac 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.

Where this sits nationally

Among the 3,058 rated counties on this site, Massac County, IL ranks 806 most-constrained nationally, and 37 of 101 within Illinois.

Before you act on this

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