Gilpin County's SSURGO septic rating
Very limited
Gilpin County, CO's SSURGO dominant class comes back "Very limited", covering 99% of the county. That reading means a conventional system is a poor bet here - 99% of Gilpin County lands in the strictest "very limited" bucket USDA uses. The county spans 150.023 square miles, home to 5,963 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Gilpin County, CO 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.
Gilpin County: conventional vs. engineered cost
99% of Gilpin 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, Gilpin County, CO ranks 102 most-constrained nationally, and 1 of 63 within Colorado.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems