Towner County's SSURGO septic rating
Very limited
Towner County, ND's SSURGO dominant class comes back "Very limited", covering 95.4% of the county. Practically, that rules out a simple gravity system for most of the county - 95.4% of it sits in USDA's most-constrained bucket. The county spans 1,025.129 square miles, home to 2,051 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Towner County, ND at once, not any single address. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Towner County: conventional vs. engineered cost
95.4% of Towner 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, Towner County, ND ranks 621 most-constrained nationally, and 2 of 53 within North Dakota.
Before you act on this
How this rating is built, and its real limits · Conventional vs. engineered septic systems