Brazos County's SSURGO septic rating
Very limited
Brazos County, TX: USDA's soil survey calls 96.5% 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 96.5% of Brazos County's land. The county spans 586.15 square miles, home to 249,624 people.
What this number does and doesn't tell you
Brazos County's rating is an average across the whole county, not a promise about any one lot inside it. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Brazos County: conventional vs. engineered cost
96.5% of Brazos 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, Brazos County, TX ranks 447 most-constrained nationally, and 26 of 253 within Texas.
Before you act on this
How this rating is built, and its real limits · Conventional vs. engineered septic systems