Mackinac County's SSURGO septic rating

Very limited

Mackinac County, MI: USDA's soil survey calls 97.2% of the county "Very limited" for a septic leach field. Practically, that rules out a simple gravity system for most of the county - 97.2% of it sits in USDA's most-constrained bucket. The county spans 1,021.879 square miles, home to 11,144 people.

What this number does and doesn't tell you

Nothing about Mackinac County, MI's SSURGO figure applies to a specific address - it's a county-wide average. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.

Mackinac County: conventional vs. engineered cost

97.2% of Mackinac 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.

Mackinac County's rank among Michigan counties

Among the 3,058 rated counties on this site, Mackinac County, MI ranks 362 most-constrained nationally, and 13 of 83 within Michigan.

Before you act on this

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