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Monterey County, California

Shrink-swell clay limits houses without basements on 15% of Monterey County's mapped land, a higher share than 63% of US counties. A shallow water table limits basements on 2%.

None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 252 flood losses here since 2016, 4% of them in buildings with basements. 58% of homes were built before 1980, against 50% nationally; the median home dates from 1976.

Data as of October 13, 2026 · sources

15%

expansive clay: shrink-swell limits slab homes

2%

high water table: limits basements

0%

in drought, October 13, 2026

58%

of homes built before 1980

Soil under Monterey County

Expansive clay (limits slab homes)15.1%
High water table (limits basements)2.1%
Septic fields very limited77.0%
Clay swell (LEP, by area)3.5%
High-swell land (LEP 6%+)16.3%
Mapped soil2,032,075 acres
Soil seriesShare hereSeries nationally: expansive clay
Cieneba6%n/a
Santa Lucia5%n/a
Sheridan5%n/a
Shedd5%n/a
Sur4%n/a
Nacimiento4%n/a
San Benito County: 21%Santa Cruz County: 10%Santa Clara County: 24%Merced County: 28%San Luis Obispo County: 17%Kings County: 32%Stanislaus County: 24%Fresno County: 14%Monterey County San BenitoSanta CruzSanta ClaraMercedSan Luis ObispoKingsStanislausFresnoMonterey
Monterey 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 CA053 (2025-09-08), CA788 (2025-09-02)

What the numbers mean here

Clay swell averages a linear extensibility of 3.5% by land area here, and 16% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 15% of the mapped land.

Rain over the 12 months to August 2026: 23.21 in, 2.19 in above the 1991-2020 average year of 21.02 in.

USDA rates 77% of the land very limited for septic absorption fields.

Drought

0% of the county is in drought (D1 or worse) on the October 13, 2026 map. No part of the county was in drought in the last 52 weeks.

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

Flood losses since 2016

252 flood losses since 2016, $16.0 million paid. The worst year was 2023, with 170. Foundations of the buildings, where recorded: 4% basements, 46% slabs, 41% crawl spaces, 9% elevated. Median water depth outside the building: 19 in.

YearFlood losses
20168
201742
20183
20196
20200
20216
202213
2023170
20244
20250
2026 to date0

Rain

Average year, 1991-202021.02 in
12 months to August 202623.21 in (+2.19)
202520.27 in (-0.75)
Wettest year since 18951983: 41.48 in
Driest year since 18952013: 4.18 in
Days with 1 inch or more, normal at KING CITY (10 mi away)2.1

Homes

Housing units145,469
Median year built1976
Built before 198058%
Built 2000 or later16%
Owner-occupied52%
Median value, owner-occupied$781,000
Single-family detached63%

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
San Benito County, CA 29 mi 21% 4%
Santa Cruz County, CA 66 mi 10% 1%
Santa Clara County, CA 71 mi 24% 3%
Merced County, CA 74 mi 28% 27%
San Luis Obispo County, CA 76 mi 17% 1%
Kings County, CA 85 mi 32% 33%
Stanislaus County, CA 93 mi 24% 7%
Fresno County, CA 99 mi 14% 2%

Sources: USDA SSURGO (September 8, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status