What Fond du Lac County, WI's soil rates for a septic system

Very limited

69.1% of Fond du Lac County, WI's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. Fond du Lac County covers 719.566 square miles and counts 104,269 residents.

This is a county figure, not a parcel figure

Two lots a mile apart in Fond du Lac County can carry different soil, even though they share one countywide rating. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Fond du Lac County.

System cost, conventional vs. engineered

Given Fond du Lac 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.

Fond du Lac County's rank among Wisconsin counties

Nationally, Fond du Lac County, WI is the 2,491-most-constrained of 3,058 rated counties for septic soil. Within Wisconsin alone it ranks 71 of 72.

Further reading

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