Dallam County's SSURGO septic rating
Somewhat limited
Dallam County, TX: USDA's soil survey calls 79.9% of the county "Somewhat limited" for a septic leach field. Modification usually rescues a conventional system at this rating - added fill or a larger field - rather than forcing a full engineered redesign. The county spans 1,503.353 square miles, home to 7,526 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Dallam County, TX 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.
Dallam County: conventional vs. engineered cost
79.9% of Dallam County carrying a "Somewhat 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.
Dallam County's rank among Texas counties
Among the 3,058 rated counties on this site, Dallam County, TX ranks 3,041 most-constrained nationally, and 247 of 253 within Texas.
Related guides
How this rating is built, and its real limits · How a percolation test actually works