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Shasta County, California

USDA's soil survey flags shrink-swell clay on 9% of Shasta County's mapped land and a shallow water table under basements on 4%, both below the national shares of 15% and 29%. The soil survey maps 77% of the county's land area; these shares describe the mapped part.

1.4% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 70 flood losses here since 2016, 3% of them in buildings with basements. 46% of homes were built before 1980, against 50% nationally; the median home dates from 1982.

Data as of October 13, 2026 · sources

9%

expansive clay: shrink-swell limits slab homes

4%

high water table: limits basements

1%

in drought, October 13, 2026

46%

of homes built before 1980

Soil under Shasta County

Expansive clay (limits slab homes)8.5%
High water table (limits basements)4.0%
Septic fields very limited84.0%
Clay swell (LEP, by area)3.1%
High-swell land (LEP 6%+)8.7%
Mapped soil1,862,764 acres
Soil seriesShare hereSeries nationally: expansive clay
Cohasset6%n/a
Newtown2%n/a
Toomes2%n/a
Aiken2%n/a
Red Bluff2%n/a
Guenoc2%n/a
Tehama County: 15%Trinity County: no dataSiskiyou County: 11%Lassen County: 21%Butte County: 31%Glenn County: 38%Plumas County: 4%Modoc County: 27%Shasta County TehamaTrinitySiskiyouLassenButteGlennPlumasModocShasta
Shasta 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 CA604 (2025-09-03), CA607 (2025-09-03), CA708 (2025-09-03), CA789 (2025-09-03)

What the numbers mean here

Rain over the 12 months to August 2026: 40.58 in, 2.56 in below the 1991-2020 average year of 43.14 in.

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

With shrink-swell clay on 9% and a shallow water table on 4% of the land, the soil survey points to neither problem across most of Shasta County; conditions still vary lot by lot.

Drought

1.4% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 7 of the last 52 weeks; the most was 1.4% of its area, in 7 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 worse1.4%
D2 severe or worse0%
D3 extreme or worse0%
D4 exceptional0%

Flood losses since 2016

70 flood losses since 2016, $3.2 million paid. The worst year was 2017, with 30. Foundations of the buildings, where recorded: 3% basements, 42% slabs, 42% crawl spaces, 13% elevated. Median water depth outside the building: 10 in.

YearFlood losses
20167
201730
20180
20194
20200
20210
20220
20234
20242
202523
2026 to date0

Rain

Average year, 1991-202043.14 in
12 months to August 202640.58 in (-2.56)
202544.12 in (+0.98)
Wettest year since 18951983: 80.27 in
Driest year since 18952013: 14.77 in
Days with 1 inch or more, normal at BUCKHORN (13 mi away)24.6

Homes

Housing units80,068
Median year built1982
Built before 198046%
Built 2000 or later19%
Owner-occupied66%
Median value, owner-occupied$366,400
Single-family detached71%

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
Tehama County, CA 45 mi 15% 3%
Trinity County, CA 57 mi n/a n/a
Siskiyou County, CA 63 mi 11% 11%
Lassen County, CA 75 mi 21% 6%
Butte County, CA 79 mi 31% 27%
Glenn County, CA 82 mi 38% 15%
Plumas County, CA 83 mi 4% 2%
Modoc County, CA 90 mi 27% 15%

Sources: USDA SSURGO (September 3, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status