San Miguel County's SSURGO septic rating

Very limited

San Miguel County, NM's SSURGO dominant class comes back "Very limited", covering 85.4% of the county. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 85.4% of the county. For scale: 4,721.515 square miles and 26,428 people call San Miguel County home.

Before you rely on this for one lot

USDA's survey covers the whole of San Miguel County, NM at once, not any single address. The real answer for one lot is still a site-specific perc test, running about $750-$1,850 (typically near $1,300).

Budgeting for a system in San Miguel County, NM

San Miguel County's soil reading pushes the likely outcome toward an engineered system rather than a conventional one. Conventional systems run $3,000-$8,000 where they pass; where they don't, engineered alternatives (mound or aerobic treatment, whichever the health department requires) run $10,000-$40,000 - budget toward the higher figure until a perc test says otherwise.

Where this sits nationally

Among the 3,058 rated counties on this site, San Miguel County, NM ranks 1,660 most-constrained nationally, and 3 of 29 within New Mexico.

Further reading

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