Septic soil in Union County, NM, by the numbers

Very limited

In Union County, NM, 73.3% of the surveyed land carries a "Very limited" rating for a standard septic drain field. That reading means a conventional system is a poor bet here - 73.3% of Union County lands in the strictest "very limited" bucket USDA uses. Union County covers 3,825.05 square miles and counts 3,926 residents.

This is a county figure, not a parcel figure

Union County's rating is an average across the whole county, not a promise about any one lot inside it. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Union County.

System cost, conventional vs. engineered

Given Union 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 Union County, NM compares

Nationally, Union County, NM is the 2,362-most-constrained of 3,058 rated counties for septic soil. Within New Mexico alone it ranks 12 of 29.

Further reading

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