Zapata County's SSURGO septic rating
Very limited
USDA puts Zapata County, TX at "Very limited" for septic absorption fields, the dominant reading across 41% of the county's soil. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 41% of the county. The county spans 998.415 square miles, home to 13,819 people.
What this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in Zapata County, TX - never a reading for one specific parcel. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Zapata County: conventional vs. engineered cost
41% of Zapata 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, Zapata County, TX ranks 2,911 most-constrained nationally, and 232 of 253 within Texas.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems