Oklahoma County, OK's soil, for a septic absorption field

Very limited

In Oklahoma County, OK, 79.4% 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. Oklahoma County covers 708.9 square miles and counts 816,490 residents.

This is a county figure, not a parcel figure

Two lots a mile apart in Oklahoma County can carry different soil, even though they share one countywide rating. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Oklahoma County.

System cost, conventional vs. engineered

Given Oklahoma 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, Oklahoma County, OK is the 2,066-most-constrained of 3,058 rated counties for septic soil. Within Oklahoma alone it ranks 54 of 77.

Before you act on this

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