Jefferson County, CO's soil, for a septic absorption field

Very limited

85.5% of Jefferson County, CO's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. Jefferson County, CO is 764.424 square miles with a population of 578,533.

What Jefferson County's reading doesn't cover

Nothing about Jefferson County, CO's SSURGO figure applies to a specific address - it's a county-wide average. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Jefferson County will actually do.

What a system would cost here

With 85.5% of Jefferson County rating "Very limited", a standard gravity system is not a safe assumption here. 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.

Jefferson County's rank among Colorado counties

Nationally, Jefferson County, CO is the 1,651-most-constrained of 3,058 rated counties for septic soil. Within Colorado alone it ranks 34 of 63.

Related guides

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