Nassau County, Florida
A shallow water table limits basements on 93% of Nassau County's mapped land, a higher share than 97% of US counties and the 6th highest of 66 Florida counties. Shrink-swell clay limits houses without basements on 7%.
None of the county is in drought on the October 13, 2026 Drought Monitor map, after 0.5% a week earlier. FEMA's flood data list 359 flood losses here since 2016, under 1% of them in buildings with basements. 20% of homes were built before 1980, against 50% nationally; the median home dates from 2000.
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 Nassau County
| Expansive clay (limits slab homes) | 6.6% |
| High water table (limits basements) | 92.9% |
| Septic fields very limited | 95.7% |
| Clay swell (LEP, by area) | 3.5% |
| High-swell land (LEP 6%+) | 19.4% |
| Mapped soil | 428,375 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Goldhead | 15% | n/a |
| Leon | 11% | n/a |
| Boulogne | 8% | n/a |
| Meggett | 7% | n/a |
| Buccaneer | 6% | n/a |
| Tisonia | 6% | n/a |
How we count · survey areas FL089 (2025-09-02)
What the numbers mean here
On 93% of Nassau 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: 35.49 in, 15.47 in below the 1991-2020 average year of 50.96 in.
USDA rates 96% 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 48 of the last 52 weeks; the most was 100% of its area, in 41 weeks, most recently on the September 1, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0.4% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
359 flood losses since 2016, $9.1 million paid. The worst year was 2017, with 178. Foundations of the buildings, where recorded: under 1% basements, 55% slabs, 14% crawl spaces, 30% elevated. Median water depth outside the building: 11.5 in.
| Year | Flood losses |
|---|---|
| 2016 | 101 |
| 2017 | 178 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 5 |
| 2021 | 7 |
| 2022 | 17 |
| 2023 | 4 |
| 2024 | 44 |
| 2025 | 3 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 50.96 in |
| 12 months to August 2026 | 35.49 in (-15.47) |
| 2025 | 43.13 in (-7.83) |
| Wettest year since 1895 | 1947: 75.60 in |
| Driest year since 1895 | 1931: 30.84 in |
| Days with 1 inch or more, normal at JACKSONVILLE (9 mi away) | 15.9 |
Homes
| Housing units | 45,058 |
| Median year built | 2000 |
| Built before 1980 | 20% |
| Built 2000 or later | 50% |
| Owner-occupied | 83% |
| Median value, owner-occupied | $382,800 |
| Single-family detached | 66% |
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 |
|---|---|---|---|
| Duval County, FL | 20 mi | 6% | 78% |
| Camden County, GA | 22 mi | 23% | 92% |
| Charlton County, GA | 24 mi | 1% | 99% |
| Baker County, FL | 37 mi | 0% | 99% |
| Brantley County, GA | 43 mi | under 1% | 96% |
| Clay County, FL | 43 mi | under 1% | 68% |
| Glynn County, GA | 45 mi | 30% | 87% |
| Ware County, GA | 50 mi | 0% | 98% |
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