Septic soil in McLennan County, TX, by the numbers

Very limited

In McLennan County, TX, 93% of the surveyed land carries a "Very limited" rating for a standard septic drain field. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. McLennan County covers 1,036.706 square miles and counts 270,358 residents.

This is a county figure, not a parcel figure

USDA's survey covers the whole of McLennan County, TX at once, not any single address. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in McLennan County.

System cost, conventional vs. engineered

Given McLennan 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.

How McLennan County, TX compares

Nationally, McLennan County, TX is the 922-most-constrained of 3,058 rated counties for septic soil. Within Texas alone it ranks 62 of 253.

Before you act on this

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