St. Louis city, Missouri
A shallow water table limits basements on 32% of St. Louis city's mapped land, a higher share than 51% of US counties. Shrink-swell clay limits houses without basements on 1%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 42 flood losses here since 2016, 72% of them in buildings with basements. 86% of homes were built before 1980, against 50% nationally; the median home dates from 1939 or earlier.
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. Louis city
| Expansive clay (limits slab homes) | 1.4% |
| High water table (limits basements) | 32.3% |
| Septic fields very limited | 34.5% |
| Clay swell (LEP, by area) | 4.5% |
| High-swell land (LEP 6%+) | 1.4% |
| Urban land, not rated | 57.5% |
| Mapped soil | 42,340 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Harvester | 18% | n/a |
| Fishpot | 5% | n/a |
| Winfield | 4% | n/a |
| Nevin | 3% | n/a |
| Menfro | 3% | 0% |
| Freeburg | 1% | n/a |
What the numbers mean here
On 32% of St. Louis city'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: 36.01 in, 5.78 in below the 1991-2020 average year of 41.79 in.
Drought
0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 17 of the last 52 weeks; the most was 100% of its area, in 15 weeks, most recently on the February 10, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
42 flood losses since 2016, $2.6 million paid. The worst year was 2022, with 22. Foundations of the buildings, where recorded: 72% basements, 24% slabs, 3% crawl spaces. Median water depth outside the building: 26 in.
| Year | Flood losses |
|---|---|
| 2016 | 2 |
| 2017 | 2 |
| 2018 | 0 |
| 2019 | 9 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 22 |
| 2023 | 5 |
| 2024 | 2 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 41.79 in |
| 12 months to August 2026 | 36.01 in (-5.78) |
| 2025 | 36.25 in (-5.54) |
| Wettest year since 1895 | 2015: 57.25 in |
| Driest year since 1895 | 1930: 23.33 in |
| Days with 1 inch or more, normal at ST LOUIS LAMBERT INTL AP (11 mi away) | 11 |
Homes
| Housing units | 174,111 |
| Median year built | 1939 or earlier |
| Built before 1980 | 86% |
| Built 2000 or later | 8% |
| Owner-occupied | 45% |
| Median value, owner-occupied | $197,500 |
| Single-family detached | 43% |
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. Louis County, MO | 11 mi | 5% | 37% |
| St. Clair County, IL | 21 mi | 28% | 73% |
| Madison County, IL | 23 mi | 33% | 73% |
| Monroe County, IL | 25 mi | 20% | 59% |
| St. Charles County, MO | 25 mi | 41% | 62% |
| Jefferson County, MO | 31 mi | 37% | 34% |
| Jersey County, IL | 31 mi | 22% | 53% |
| Calhoun County, IL | 43 mi | 4% | 25% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status