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Rio Arriba County, New Mexico

USDA's soil survey flags shrink-swell clay on 14% of Rio Arriba County's mapped land and a shallow water table under basements on 3%, both below the national shares of 15% and 29%. 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 1 flood losses here since 2016. 44% of homes were built before 1980, against 50% nationally; the median home dates from 1984.

Data as of October 13, 2026 · sources

14%

expansive clay: shrink-swell limits slab homes

3%

high water table: limits basements

100%

in drought, October 13, 2026

44%

of homes built before 1980

Soil under Rio Arriba County

Expansive clay (limits slab homes)14.4%
High water table (limits basements)3.0%
Septic fields very limited83.8%
Clay swell (LEP, by area)3.7%
High-swell land (LEP 6%+)14.3%
Mapped soil3,230,458 acres
Soil seriesShare hereSeries nationally: expansive clay
Orlie6%n/a
Vessilla5%n/a
Menefee5%n/a
Florita2%n/a
Pinavetes2%n/a
Angostura2%n/a
Los Alamos County: 25%Archuleta County: 53%Conejos County: 0%Sandoval County: 7%Taos County: 12%Rio Grande County: 0%Mineral County: 1%Santa Fe County: 6%Rio Arriba County Los AlamosArchuletaConejosSandovalTaosRio GrandeMineralSanta FeRio Arriba
Rio Arriba County (heavy outline) and nearby counties, shaded by expansive clay share.under 10%10-25%25-40%40-60%60%+

How we count · survey areas NM650 (2025-09-09), NM656 (2025-09-09), NM670 (2025-09-09), NM672 (2025-09-09), NM698 (2025-09-09)

What the numbers mean here

Rain over the 12 months to August 2026: 12.24 in, 4.13 in below the 1991-2020 average year of 16.37 in.

USDA rates 84% of the land very limited for septic absorption fields.

With shrink-swell clay on 14% and a shallow water table on 3% of the land, the soil survey points to neither problem across most of Rio Arriba County; conditions still vary lot by lot.

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 52 of the last 52 weeks; the most was 100% of its area, in 30 weeks, most recently on the October 13, 2026 map.

October 21, 2025Share of area in drought, weeklyOctober 13, 2026
Category, October 13, 2026Share of county
D0 abnormally dry or worse100%
D1 moderate drought or worse100%
D2 severe or worse90.9%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

1 flood losses since 2016, $8,560 paid. The worst year was 2018, with 1.

YearFlood losses
20160
20170
20181
20190
20200
20210
20220
20230
20240
20250
2026 to date0

Rain

Average year, 1991-202016.37 in
12 months to August 202612.24 in (-4.13)
202513.32 in (-3.05)
Wettest year since 18951941: 27.16 in
Driest year since 18951956: 7.51 in
Days with 1 inch or more, normal at EL VADO DAM (6 mi away)0.8

Homes

Housing units19,862
Median year built1984
Built before 198044%
Built 2000 or later19%
Owner-occupied80%
Median value, owner-occupied$243,700
Single-family detached59%

What repairs cost

Published ranges from cost guides, not quotes. More sources, and where they disagree.

WorkRangeSource
Foundation repair, US $2,200 to $8,200 Fixr, January 27, 2026
Pier-and-beam repair, US $2,000 to $15,000 Fixr, January 27, 2026
Foundation inspection, US $300 to $600 Fixr, January 31, 2025

Nearby counties

PlaceDistanceExpansive clayHigh water table
Los Alamos County, NM 49 mi 25% 0%
Archuleta County, CO 52 mi 53% 3%
Conejos County, CO 56 mi under 1% 28%
Sandoval County, NM 58 mi 7% 1%
Taos County, NM 59 mi 12% 2%
Rio Grande County, CO 69 mi under 1% 42%
Mineral County, CO 76 mi 1% 5%
Santa Fe County, NM 80 mi 6% under 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