St. James Parish, Louisiana
A shallow water table limits basements on 92% of St. James Parish's mapped land, a higher share than 97% of US counties and the 4th highest of 64 Louisiana counties. Shrink-swell clay limits houses without basements on 68%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map, up from 0% a week earlier. FEMA's flood data list 120 flood losses here since 2016, 0% of them in buildings with basements. 44% of homes were built before 1980, against 50% nationally; the median home dates from 1985.
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 St. James Parish
| Expansive clay (limits slab homes) | 68.3% |
| High water table (limits basements) | 91.6% |
| Septic fields very limited | 91.3% |
| Clay swell (LEP, by area) | 13.9% |
| High-swell land (LEP 6%+) | 70.4% |
| Mapped soil | 162,500 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Barbary | 35% | n/a |
| Schriever | 19% | n/a |
| Cancienne | 16% | n/a |
| Gramercy | 7% | n/a |
| Fausse | 5% | n/a |
| Carville | 4% | n/a |
How we count · survey areas LA093 (2025-08-28)
What the numbers mean here
Clay swell averages a linear extensibility of 13.9% by land area here, and 70% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 68% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 68% of St. James Parish's mapped land has shrink-swell clay.
On 92% of St. James Parish'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: 54.92 in, 9.18 in below the 1991-2020 average year of 64.10 in.
USDA rates 91% 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 24 of the last 52 weeks; the most was 100% of its area, in 8 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 | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
120 flood losses since 2016, $2.5 million paid. The worst year was 2021, with 50. Foundations of the buildings, where recorded: 89% slabs, 1% crawl spaces, 10% elevated. Median water depth outside the building: 6 in.
| Year | Flood losses |
|---|---|
| 2016 | 37 |
| 2017 | 2 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 4 |
| 2021 | 50 |
| 2022 | 1 |
| 2023 | 0 |
| 2024 | 26 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 64.10 in |
| 12 months to August 2026 | 54.92 in (-9.18) |
| 2025 | 52.81 in (-11.29) |
| Wettest year since 1895 | 1991: 88.27 in |
| Driest year since 1895 | 1924: 38.57 in |
| Days with 1 inch or more, normal at DONALDSONVILLE 4 SW (14 mi away) | 20.3 |
Homes
| Housing units | 8,678 |
| Median year built | 1985 |
| Built before 1980 | 44% |
| Built 2000 or later | 32% |
| Owner-occupied | 84% |
| Median value, owner-occupied | $211,800 |
| Single-family detached | 74% |
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 |
|---|---|---|---|
| Ascension Parish, LA | 14 mi | 46% | 91% |
| Assumption Parish, LA | 18 mi | 68% | 88% |
| St. John the Baptist Parish, LA | 20 mi | 43% | 61% |
| St. Charles Parish, LA | 27 mi | 44% | 63% |
| Livingston Parish, LA | 29 mi | 27% | 86% |
| Iberville Parish, LA | 38 mi | 54% | 88% |
| East Baton Rouge Parish, LA | 40 mi | 7% | 72% |
| West Baton Rouge Parish, LA | 43 mi | 44% | 81% |
Sources: USDA SSURGO (August 28, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status