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Sacramento County, California
A shallow water table limits basements on 26% of Sacramento County's mapped land and the 6th highest of 54 California counties. Shrink-swell clay limits houses without basements on 16%.
None of the county is in drought on the September 22, 2026 Drought Monitor map. FEMA's flood data list 418 flood losses here since 2016, 4% of them in buildings with basements. 48% of homes were built before 1980, against 50% nationally; the median home dates from 1981.
Data as of September 22, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, September 22, 2026
of homes built before 1980
Soil under Sacramento County
| Expansive clay (limits slab homes) | 16.3% |
| High water table (limits basements) | 26.3% |
| Septic fields very limited | 73.1% |
| Clay swell (LEP, by area) | 5.5% |
| High-swell land (LEP 6%+) | 37.3% |
| Urban land, not rated | 6.6% |
| Mapped soil | 636,148 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| San Joaquin | 18% | n/a |
| Redding | 6% | n/a |
| Galt | 4% | n/a |
| Gazwell | 4% | n/a |
| Clear Lake | 3% | n/a |
| Sailboat | 3% | n/a |
How we count · survey areas CA067 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 5.5% by land area here, and 37% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 16% of the mapped land.
On 26% of Sacramento County's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
Rain over the 12 months to August 2026: 20.09 in, 0.60 in above the 1991-2020 average year of 19.49 in.
USDA rates 73% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the September 22, 2026 map. No part of the county was in drought in the last 52 weeks.
| Category, September 22, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 53.4% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
418 flood losses since 2016, $6.4 million paid. The worst year was 2017, with 148. Foundations of the buildings, where recorded: 4% basements, 65% slabs, 25% crawl spaces, 5% elevated. Median water depth outside the building: 8 in.
| Year | Flood losses |
|---|---|
| 2016 | 21 |
| 2017 | 148 |
| 2018 | 12 |
| 2019 | 12 |
| 2020 | 9 |
| 2021 | 41 |
| 2022 | 40 |
| 2023 | 104 |
| 2024 | 16 |
| 2025 | 8 |
| 2026 to date | 7 |
Rain
| Average year, 1991-2020 | 19.49 in |
| 12 months to August 2026 | 20.09 in (+0.60) |
| 2025 | 16.54 in (-2.95) |
| Wettest year since 1895 | 1983: 38.42 in |
| Driest year since 1895 | 1976: 6.24 in |
| Days with 1 inch or more, normal at SACRAMENTO 5 ESE (8 mi away) | 3.8 |
Homes
| Housing units | 598,385 |
| Median year built | 1981 |
| Built before 1980 | 48% |
| Built 2000 or later | 22% |
| Owner-occupied | 59% |
| Median value, owner-occupied | $534,200 |
| Single-family detached | 65% |
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 |
|---|---|---|---|
| Yolo County, CA | 34 mi | 44% | 23% |
| Solano County, CA | 35 mi | 50% | 21% |
| San Joaquin County, CA | 36 mi | 30% | 23% |
| Amador County, CA | 37 mi | 1% | 3% |
| Sutter County, CA | 45 mi | 41% | 37% |
| Calaveras County, CA | 46 mi | 2% | 2% |
| El Dorado County, CA | 49 mi | 1% | 2% |
| Contra Costa County, CA | 50 mi | 48% | 11% |
Sources: USDA SSURGO (September 2, 2025) · US Drought Monitor (September 22, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status