Septic soil in Alcona County, MI, by the numbers

Very limited

Soil across 88.6% of Alcona County, MI rates "Very limited" in USDA's septic-absorption-field interpretation. Practically, that rules out a simple gravity system for most of the county - 88.6% of it sits in USDA's most-constrained bucket. Alcona County covers 674.655 square miles and counts 10,624 residents.

This is a county figure, not a parcel figure

USDA's survey covers the whole of Alcona County, MI at once, not any single address. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Alcona County.

System cost, conventional vs. engineered

Given Alcona 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.

Alcona County's rank among Michigan counties

Nationally, Alcona County, MI is the 1,412-most-constrained of 3,058 rated counties for septic soil. Within Michigan alone it ranks 63 of 83.

Before you act on this

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