St. Croix County, WI: the USDA septic-suitability picture

Very limited

USDA puts St. Croix County, WI at "Very limited" for septic absorption fields, the dominant reading across 80.6% of the county's soil. That reading means a conventional system is a poor bet here - 80.6% of St. Croix County lands in the strictest "very limited" bucket USDA uses. The county spans 722.158 square miles, home to 97,954 people.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in St. Croix County, WI - 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.

St. Croix County: conventional vs. engineered cost

80.6% of St. Croix 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, St. Croix County, WI ranks 2,009 most-constrained nationally, and 67 of 72 within Wisconsin.

Further reading

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