Macon County, Missouri
A shallow water table limits basements on 95% of Macon County's mapped land, a higher share than 99% of US counties and the 5th highest of 115 Missouri counties. Shrink-swell clay limits houses without basements on 80%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list no flood losses here since 2016. 62% of homes were built before 1980, against 50% nationally; the median home dates from 1972.
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 Macon County
| Expansive clay (limits slab homes) | 79.8% |
| High water table (limits basements) | 95.1% |
| Septic fields very limited | 98.6% |
| Clay swell (LEP, by area) | 7.4% |
| High-swell land (LEP 6%+) | 79.4% |
| Mapped soil | 520,026 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Armstrong | 16% | over 99% |
| Keswick | 15% | n/a |
| Winnegan | 12% | n/a |
| Purdin | 7% | n/a |
| Adco | 6% | n/a |
| Leonard | 6% | n/a |
How we count · survey areas MO121 (2025-09-02)
What the numbers mean here
Clay swell averages a linear extensibility of 7.4% by land area here, and 79% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 80% of the mapped land.
On 95% of Macon 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: 34.55 in, 6.68 in below the 1991-2020 average year of 41.23 in.
USDA rates 99% of the land very limited for septic absorption fields.
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 20 of the last 52 weeks; the most was 99.9% of its area, in 4 weeks, most recently on the November 18, 2025 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Macon County since 2016.
Rain
| Average year, 1991-2020 | 41.23 in |
| 12 months to August 2026 | 34.55 in (-6.68) |
| 2025 | 33.79 in (-7.44) |
| Wettest year since 1895 | 2008: 63.86 in |
| Driest year since 1895 | 1988: 20.76 in |
| Days with 1 inch or more, normal at KIRKSVILLE (26 mi away) | 11.1 |
Homes
| Housing units | 7,419 |
| Median year built | 1972 |
| Built before 1980 | 62% |
| Built 2000 or later | 18% |
| Owner-occupied | 77% |
| Median value, owner-occupied | $149,100 |
| Single-family detached | 80% |
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 |
|---|---|---|---|
| Adair County, MO | 25 mi | 68% | 95% |
| Shelby County, MO | 25 mi | 87% | 91% |
| Randolph County, MO | 27 mi | 83% | 85% |
| Linn County, MO | 29 mi | 83% | 99% |
| Chariton County, MO | 30 mi | 66% | 88% |
| Knox County, MO | 31 mi | 81% | 85% |
| Monroe County, MO | 37 mi | 84% | 85% |
| Sullivan County, MO | 39 mi | 82% | 61% |
Sources: USDA SSURGO (September 2, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status