Septic soil in Gratiot County, MI, by the numbers

Very limited

98.3% of Gratiot County, MI's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 98.3% of the county. Gratiot County covers 568.382 square miles and counts 41,372 residents.

This is a county figure, not a parcel figure

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

System cost, conventional vs. engineered

Given Gratiot 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.

Where this sits nationally

Nationally, Gratiot County, MI is the 202-most-constrained of 3,058 rated counties for septic soil. Within Michigan alone it ranks 4 of 83.

Related guides

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