Hall County's SSURGO septic rating
Very limited
USDA puts Hall County, TX at "Very limited" for septic absorption fields, the dominant reading across 73.6% of the county's soil. Practically, that rules out a simple gravity system for most of the county - 73.6% of it sits in USDA's most-constrained bucket. For scale: 883.492 square miles and 2,828 people call Hall County home.
Before you rely on this for one lot
USDA's survey covers the whole of Hall County, TX at once, not any single address. The real answer for one lot is still a site-specific perc test, running about $750-$1,850 (typically near $1,300).
Budgeting for a system in Hall County, TX
Hall County's soil reading pushes the likely outcome toward an engineered system rather than a conventional one. 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 Hall County, TX compares
Among the 3,058 rated counties on this site, Hall County, TX ranks 2,345 most-constrained nationally, and 184 of 253 within Texas.
Before you act on this
How this rating is built, and its real limits · Conventional vs. engineered septic systems