Custer County, ID Septic Rating
Custer County's SSURGO septic rating
Very limited
Custer County, ID's SSURGO dominant class comes back "Very limited", covering 87.4% of the county. 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 4,922 square miles, home to 4,597 people.
What this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in Custer County, ID - 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.
Custer County: conventional vs. engineered cost
87.4% of Custer 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.
Custer County's rank among Idaho counties
Among the 3,058 rated counties on this site, Custer County, ID ranks 1,520 most-constrained nationally, and 23 of 44 within Idaho.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems