Ascension Parish, Louisiana
A shallow water table limits basements on 91% of Ascension Parish's mapped land, a higher share than 96% of US counties and the 5th highest of 64 Louisiana counties. Shrink-swell clay limits houses without basements on 46%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map, up from 68.6% a week earlier. FEMA's flood data list 4,359 flood losses here since 2016, under 1% of them in buildings with basements. 19% of homes were built before 1980, against 50% nationally; the median home dates from 2002.
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 Ascension Parish
| Expansive clay (limits slab homes) | 45.5% |
| High water table (limits basements) | 90.6% |
| Septic fields very limited | 88.6% |
| Clay swell (LEP, by area) | 10.6% |
| High-swell land (LEP 6%+) | 45.6% |
| Mapped soil | 193,900 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Schriever | 18% | n/a |
| Barbary | 14% | n/a |
| Commerce | 11% | n/a |
| Fausse | 7% | n/a |
| Galvez | 5% | n/a |
| Thibaut | 4% | n/a |
How we count · survey areas LA005 (2025-09-05)
What the numbers mean here
Clay swell averages a linear extensibility of 10.6% by land area here, and 46% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 46% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 46% of Ascension Parish's mapped land has shrink-swell clay.
On 91% of Ascension 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: 59.47 in, 4.84 in below the 1991-2020 average year of 64.31 in.
USDA rates 89% 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 21 of the last 52 weeks; the most was 100% of its area, 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
4,359 flood losses since 2016, $327.2 million paid. The worst year was 2016, with 3,947. Foundations of the buildings, where recorded: under 1% basements, 79% slabs, 2% crawl spaces, 19% elevated. Median water depth outside the building: 15 in.
| Year | Flood losses |
|---|---|
| 2016 | 3,947 |
| 2017 | 18 |
| 2018 | 10 |
| 2019 | 24 |
| 2020 | 57 |
| 2021 | 268 |
| 2022 | 12 |
| 2023 | 1 |
| 2024 | 16 |
| 2025 | 1 |
| 2026 to date | 5 |
Rain
| Average year, 1991-2020 | 64.31 in |
| 12 months to August 2026 | 59.47 in (-4.84) |
| 2025 | 55.73 in (-8.58) |
| Wettest year since 1895 | 2021: 89.80 in |
| Driest year since 1895 | 1924: 37.82 in |
| Days with 1 inch or more, normal at GONZALES (1 mi away) | 21.6 |
Homes
| Housing units | 51,940 |
| Median year built | 2002 |
| Built before 1980 | 19% |
| Built 2000 or later | 56% |
| Owner-occupied | 81% |
| Median value, owner-occupied | $279,600 |
| 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 |
|---|---|---|---|
| St. James Parish, LA | 14 mi | 68% | 92% |
| Livingston Parish, LA | 20 mi | 27% | 86% |
| Assumption Parish, LA | 23 mi | 68% | 88% |
| St. John the Baptist Parish, LA | 26 mi | 43% | 61% |
| East Baton Rouge Parish, LA | 26 mi | 7% | 72% |
| Iberville Parish, LA | 27 mi | 54% | 88% |
| West Baton Rouge Parish, LA | 30 mi | 44% | 81% |
| St. Charles Parish, LA | 39 mi | 44% | 63% |
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