What Durham County, NC's soil rates for a septic system

Very limited

Soil across 64.4% of Durham County, NC rates "Very limited" in USDA's septic-absorption-field interpretation. That reading means a conventional system is a poor bet here - 64.4% of Durham County lands in the strictest "very limited" bucket USDA uses. Durham County covers 287.555 square miles and counts 343,628 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in Durham County, NC - 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 Durham County.

System cost, conventional vs. engineered

Given Durham 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 Durham County, NC compares

Nationally, Durham County, NC is the 2,627-most-constrained of 3,058 rated counties for septic soil. Within North Carolina alone it ranks 62 of 97.

Further reading

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