Trinity County's SSURGO septic rating

Very limited

USDA puts Trinity County, CA at "Very limited" for septic absorption fields, the dominant reading across 96.5% of the county's soil. 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. The county spans 3,179.268 square miles, home to 15,642 people.

What this number does and doesn't tell you

USDA's survey covers the whole of Trinity County, CA 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.

Trinity County: conventional vs. engineered cost

96.5% of Trinity 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.

How Trinity County, CA compares

Among the 3,058 rated counties on this site, Trinity County, CA ranks 458 most-constrained nationally, and 6 of 57 within California.

Further reading

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