HomeNew MexicoSan Miguel County
San Miguel County, New Mexico
Shrink-swell clay limits houses without basements on 23% of San Miguel County's mapped land, a higher share than 73% of US counties and the 10th highest of 33 New Mexico counties. A shallow water table limits basements on 1%.
The soil survey maps 86% of the county's land area; these shares describe the mapped part. 100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 122 flood losses here since 2016, 12% of them in buildings with basements. 52% of homes were built before 1980, against 50% nationally; the median home dates from 1979.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under San Miguel County
| Expansive clay (limits slab homes) | 22.8% |
| High water table (limits basements) | 0.9% |
| Septic fields very limited | 84.6% |
| Clay swell (LEP, by area) | 4.4% |
| High-swell land (LEP 6%+) | 24.6% |
| Mapped soil | 2,598,499 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Latom | 8% | n/a |
| Tuloso | 7% | n/a |
| Partri | 6% | n/a |
| Redona | 5% | n/a |
| Newkirk | 5% | n/a |
| La Lande | 5% | n/a |
How we count · survey areas NM630 (2025-09-09)
What the numbers mean here
Clay swell averages a linear extensibility of 4.4% by land area here, and 25% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 23% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 23% of San Miguel County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 12.12 in, 4.50 in below the 1991-2020 average year of 16.62 in.
USDA rates 85% of the land very limited for septic absorption fields.
Drought
100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 42 of the last 52 weeks; the most was 100% of its area, in 28 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 100% |
| D3 extreme or worse | 3.3% |
| D4 exceptional | 0% |
Flood losses since 2016
122 flood losses since 2016, $759,041 paid. The worst year was 2024, with 90. Foundations of the buildings, where recorded: 12% basements, 36% slabs, 47% crawl spaces, 5% elevated. Median water depth outside the building: 6 in.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 3 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 1 |
| 2021 | 0 |
| 2022 | 6 |
| 2023 | 2 |
| 2024 | 90 |
| 2025 | 17 |
| 2026 to date | 3 |
Rain
| Average year, 1991-2020 | 16.62 in |
| 12 months to August 2026 | 12.12 in (-4.50) |
| 2025 | 19.49 in (+2.87) |
| Wettest year since 1895 | 1941: 32.53 in |
| Driest year since 1895 | 1956: 7.25 in |
| Days with 1 inch or more, normal at LAS VEGAS MUNI AP (23 mi away) | 2.2 |
Homes
| Housing units | 14,867 |
| Median year built | 1979 |
| Built before 1980 | 52% |
| Built 2000 or later | 16% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $188,500 |
| Single-family detached | 56% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Mora County, NM | 36 mi | 46% | under 1% |
| Guadalupe County, NM | 42 mi | 2% | under 1% |
| Harding County, NM | 60 mi | 15% | 1% |
| Santa Fe County, NM | 65 mi | 6% | under 1% |
| Quay County, NM | 75 mi | 15% | 1% |
| Colfax County, NM | 79 mi | 52% | 2% |
| De Baca County, NM | 81 mi | 3% | 2% |
| Torrance County, NM | 89 mi | 5% | 1% |
Sources: USDA SSURGO (September 9, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status