O'Brien County, IA Septic Rating
O'Brien County's SSURGO septic rating
Very limited
USDA puts O'Brien County, IA at "Very limited" for septic absorption fields, the dominant reading across 98.8% of the county's soil. That reading means a conventional system is a poor bet here - it's already USDA's strictest "very limited" bucket, not a partial constraint. The county spans 573 square miles, home to 14,260 people.
What this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in O'Brien County, IA - 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.
O'Brien County: conventional vs. engineered cost
98.8% of O'Brien 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.
O'Brien County's rank among Iowa counties
Among the 3,058 rated counties on this site, O'Brien County, IA ranks 121 most-constrained nationally, and 10 of 99 within Iowa.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems