Arapahoe County's SSURGO septic rating

Very limited

Arapahoe County, CO: USDA's soil survey calls 58.5% of the county "Very limited" for a septic leach field. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 58.5% of Arapahoe County's land. The county spans 797.887 square miles, home to 666,918 people.

What this number does and doesn't tell you

Two lots a mile apart in Arapahoe County can carry different soil, even though they share one countywide rating. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.

Arapahoe County: conventional vs. engineered cost

58.5% of Arapahoe 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, Arapahoe County, CO ranks 2,753 most-constrained nationally, and 49 of 63 within Colorado.

Further reading

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