Grant County, ND's soil, for a septic absorption field
Very limited
83.8% of Grant County, ND's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. That reading means a conventional system is a poor bet here - 83.8% of Grant County lands in the strictest "very limited" bucket USDA uses. Grant County, ND is 1,659.233 square miles with a population of 2,247.
What Grant County's reading doesn't cover
Two lots a mile apart in Grant County can carry different soil, even though they share one countywide rating. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Grant County will actually do.
What a system would cost here
With 83.8% of Grant County rating "Very limited", a standard gravity system is not a safe assumption here. 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, Grant County, ND is the 1,804-most-constrained of 3,058 rated counties for septic soil. Within North Dakota alone it ranks 14 of 53.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems