Septic suitability in Parmer County, TX
Very limited
Parmer County, TX's SSURGO dominant class comes back "Very limited", covering 65.8% of the county. Practically, that rules out a simple gravity system for most of the county - 65.8% of it sits in USDA's most-constrained bucket. The county spans 880.822 square miles, home to 9,669 people.
What this number does and doesn't tell you
This is a countywide, area-weighted figure across every soil survey map unit in Parmer 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.
Parmer County: conventional vs. engineered cost
65.8% of Parmer 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.
Parmer County's rank among Texas counties
Among the 3,058 rated counties on this site, Parmer County, TX ranks 2,587 most-constrained nationally, and 208 of 253 within Texas.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems