Lafourche Parish, Louisiana
A shallow water table limits basements on 74% of Lafourche Parish's mapped land, a higher share than 84% of US counties. Shrink-swell clay limits houses without basements on 42%.
16.9% 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 1,046 flood losses here since 2016, 1% of them in buildings with basements. 47% of homes were built before 1980, against 50% nationally; the median home dates from 1982.
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 Lafourche Parish
| Expansive clay (limits slab homes) | 41.9% |
| High water table (limits basements) | 74.0% |
| Septic fields very limited | 70.1% |
| Clay swell (LEP, by area) | 12.0% |
| High-swell land (LEP 6%+) | 41.9% |
| Mapped soil | 828,900 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Allemands | 10% | n/a |
| Barbary | 10% | n/a |
| Schriever | 9% | n/a |
| Cancienne | 7% | n/a |
| Timbalier | 7% | n/a |
| Kenner | 5% | n/a |
How we count · survey areas LA057 (2025-09-05)
What the numbers mean here
Clay swell averages a linear extensibility of 12.0% by land area here, and 42% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 42% of the mapped land.
Clay shrinks as it dries: 16.9% of the county is in drought on the latest map, and 42% of Lafourche Parish's mapped land has shrink-swell clay.
On 74% of Lafourche 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: 49.66 in, 13.50 in below the 1991-2020 average year of 63.16 in.
USDA rates 70% of the land very limited for septic absorption fields.
Drought
16.9% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 36 of the last 52 weeks; the most was 100% of its area, in 17 weeks, most recently on the May 26, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 16.9% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
1,046 flood losses since 2016, $40.3 million paid. The worst year was 2021, with 628. Foundations of the buildings, where recorded: 1% basements, 69% slabs, 4% crawl spaces, 26% elevated. Median water depth outside the building: 12 in.
| Year | Flood losses |
|---|---|
| 2016 | 17 |
| 2017 | 49 |
| 2018 | 3 |
| 2019 | 24 |
| 2020 | 93 |
| 2021 | 628 |
| 2022 | 4 |
| 2023 | 2 |
| 2024 | 140 |
| 2025 | 5 |
| 2026 to date | 81 |
Rain
| Average year, 1991-2020 | 63.16 in |
| 12 months to August 2026 | 49.66 in (-13.50) |
| 2025 | 51.25 in (-11.91) |
| Wettest year since 1895 | 1991: 91.92 in |
| Driest year since 1895 | 1962: 38.46 in |
| Days with 1 inch or more, normal at GALLIANO (6 mi away) | 22 |
Homes
| Housing units | 41,447 |
| Median year built | 1982 |
| Built before 1980 | 47% |
| Built 2000 or later | 28% |
| Owner-occupied | 80% |
| Median value, owner-occupied | $193,900 |
| Single-family detached | 72% |
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 |
|---|---|---|---|
| Jefferson Parish, LA | 20 mi | 27% | 44% |
| St. Charles Parish, LA | 29 mi | 44% | 63% |
| Terrebonne Parish, LA | 29 mi | 34% | 65% |
| St. James Parish, LA | 44 mi | 68% | 92% |
| St. John the Baptist Parish, LA | 45 mi | 43% | 61% |
| Orleans Parish, LA | 48 mi | 29% | 37% |
| Assumption Parish, LA | 49 mi | 68% | 88% |
| Plaquemines Parish, LA | 51 mi | 20% | 39% |
Sources: USDA SSURGO (September 5, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status