Williams County, ND's soil, for a septic absorption field

Very limited

Soil across 57.4% of Williams County, ND rates "Very limited" in USDA's septic-absorption-field interpretation. Practically, that rules out a simple gravity system for most of the county - 57.4% of it sits in USDA's most-constrained bucket. Williams County covers 2,077.6 square miles and counts 40,763 residents.

This is a county figure, not a parcel figure

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

System cost, conventional vs. engineered

Given Williams 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.

How Williams County, ND compares

Nationally, Williams County, ND is the 2,773-most-constrained of 3,058 rated counties for septic soil. Within North Dakota alone it ranks 37 of 53.

Related guides

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