Allegany County, New York
A shallow water table limits basements on 80% of Allegany County's mapped land, a higher share than 89% of US counties and the 2nd highest of 62 New York counties. Shrink-swell clay limits houses without basements on 0%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 4 flood losses here since 2016. 68% of homes were built before 1980, against 50% nationally; the median home dates from 1966.
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 Allegany County
| Expansive clay (limits slab homes) | 0.0% |
| High water table (limits basements) | 79.9% |
| Septic fields very limited | 99.3% |
| Clay swell (LEP, by area) | 1.6% |
| High-swell land (LEP 6%+) | 0.0% |
| Mapped soil | 661,410 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Ontusia | 9% | n/a |
| Volusia | 8% | over 99% |
| Napoli | 7% | n/a |
| Ischua | 6% | n/a |
| Mongaup | 6% | n/a |
| Wiscoy | 4% | n/a |
How we count · survey areas NY003 (2025-08-29)
What the numbers mean here
On 80% of Allegany 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: 41.59 in, 1.31 in above the 1991-2020 average year of 40.28 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 100% of its area, in 5 weeks, most recently on the November 18, 2025 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 53.3% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
4 flood losses since 2016, $32,932 paid. The worst year was 2021, with 2.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 2 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 40.28 in |
| 12 months to August 2026 | 41.59 in (+1.31) |
| 2025 | 36.56 in (-3.72) |
| Wettest year since 1895 | 2011: 49.81 in |
| Driest year since 1895 | 1934: 25.80 in |
| Days with 1 inch or more, normal at ANGELICA (4 mi away) | 6.3 |
Homes
| Housing units | 23,540 |
| Median year built | 1966 |
| Built before 1980 | 68% |
| Built 2000 or later | 13% |
| Owner-occupied | 79% |
| Median value, owner-occupied | $101,700 |
| 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 |
|---|---|---|---|
| Cattaraugus County, NY | 33 mi | 0% | 65% |
| Steuben County, NY | 33 mi | 0% | 63% |
| Wyoming County, NY | 33 mi | 0% | 72% |
| Potter County, PA | 35 mi | 0% | 37% |
| Livingston County, NY | 36 mi | 24% | 78% |
| McKean County, PA | 41 mi | 0% | 54% |
| Tioga County, PA | 52 mi | 0% | 49% |
| Erie County, NY | 52 mi | 6% | 66% |
Sources: USDA SSURGO (August 29, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status