HomeOhioAuglaize CountySt. Marys
St. Marys, Ohio
Inside St. Marys' city limits, a shallow water table limits basements on 68% of mapped land, higher than 53% of Ohio cities. Shrink-swell clay limits houses without basements on 11%.
That water-table share is below Auglaize County's 94%. FEMA's flood data list 16 flood losses since 2016 in ZIP code 45885 overlapping the city. Of its 3,714 homes, 81% were built before 1980; the median dates from 1952.
Data as of October 13, 2026 · sources · in Auglaize County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 1 overlapping ZIP
of homes built before 1980
Basement waterproofing in St. Marys
Basement waterproofing in St. Marys: a shallow water table limits basements on 68% of St. Marys' mapped land, more than in 53% of Ohio cities, and the ZIP code overlapping St. Marys logged 16 FEMA flood losses since 2016.
About 3,000 of St. Marys' 3,714 homes are detached houses.
Soil under St. Marys city limits
| Expansive clay (limits slab homes) | 11.5% |
| High water table (limits basements) | 68.2% |
| Septic fields very limited | 70.5% |
| Clay swell (LEP, by area) | 4.2% |
| High-swell land (LEP 6%+) | 0.7% |
| Urban land, not rated | 21.1% |
| Mapped soil | 3,006 acres |
What the numbers mean here
On 68% of St. Marys' mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 70% of the land very limited for septic absorption fields.
Drought in Auglaize County
0% of Auglaize County is in drought (D1 or worse) on the October 13, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap St. Marys. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 45885 | 100% | 16 | $410,017 |
Homes in St. Marys
| Housing units | 3,714 |
| Median year built | 1952 |
| Built before 1980 | 81% |
| Built 2000 or later | 10% |
| Owner-occupied | 79% |
| Median value, owner-occupied | $148,500 |
| Single-family detached | 81% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| New Knoxville | 5 mi | 32% | over 99% |
| New Bremen | 8 mi | 27% | 99% |
| Buckland | 9 mi | 16% | 79% |
| Celina | 9 mi | 23% | 67% |
| Montezuma | 9 mi | 24% | 92% |
| Chickasaw | 9 mi | 19% | 93% |
| Minster | 11 mi | 34% | over 99% |
| Kettlersville | 11 mi | 40% | 99% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status