Septic soil in San Patricio County, TX, by the numbers

Very limited

Soil across 70.4% of San Patricio 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 70.4% of the county. San Patricio County covers 693.32 square miles and counts 71,467 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in San Patricio County, TX - never a reading for one specific parcel. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in San Patricio County.

System cost, conventional vs. engineered

Given San Patricio 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, San Patricio County, TX is the 2,450-most-constrained of 3,058 rated counties for septic soil. Within Texas alone it ranks 198 of 253.

Related guides

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