What Castro County, TX's soil rates for a septic system

Very limited

Soil across 81% of Castro County, TX rates "Very limited" in USDA's septic-absorption-field interpretation. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 81% of the county. Castro County covers 894.444 square miles and counts 7,380 residents.

This is a county figure, not a parcel figure

Nothing about Castro County, TX's SSURGO figure applies to a specific address - it's a county-wide average. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Castro County.

System cost, conventional vs. engineered

Given Castro County's rating, plan for the engineered-system range rather than the conventional one. The engineered-system range, $10,000-$40,000 (mound or aerobic treatment), is the more realistic number to plan around, against $3,000-$8,000 for a conventional system on the rare lot that passes.

Where this sits nationally

Nationally, Castro County, TX is the 1,992-most-constrained of 3,058 rated counties for septic soil. Within Texas alone it ranks 148 of 253.

Further reading

How this rating is built, and its real limits · Conventional vs. engineered septic systems