HomeVirginiaPrince William County
Prince William County, Virginia
A shallow water table limits basements on 35% of Prince William County's mapped land, a higher share than 53% of US counties. Shrink-swell clay limits houses without basements on 9%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 101 flood losses here since 2016, 49% of them in buildings with basements. 24% of homes were built before 1980, against 50% nationally; the median home dates from 1995.
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 Prince William County
| Expansive clay (limits slab homes) | 9.3% |
| High water table (limits basements) | 34.6% |
| Septic fields very limited | 74.3% |
| Clay swell (LEP, by area) | 3.5% |
| High-swell land (LEP 6%+) | 12.4% |
| Urban land, not rated | 3.5% |
| Mapped soil | 230,786 acres |
| Soil series | Share here | Series nationally: high water table |
|---|---|---|
| Arcola | 11% | n/a |
| Buckhall | 5% | n/a |
| Manassas | 4% | n/a |
| Albano | 4% | n/a |
| Waxpool | 3% | n/a |
| Gaila | 3% | n/a |
How we count · survey areas VA153 (2025-09-05)
What the numbers mean here
On 35% of Prince William 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: 32.73 in, 9.39 in below the 1991-2020 average year of 42.12 in.
USDA rates 74% 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 49 of the last 52 weeks; the most was 100% of its area, in 41 weeks, most recently on the July 28, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 4.8% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
101 flood losses since 2016, $942,699 paid. The worst year was 2018, with 32. Foundations of the buildings, where recorded: 49% basements, 21% slabs, 2% crawl spaces, 28% elevated. Median water depth outside the building: 9.5 in.
| Year | Flood losses |
|---|---|
| 2016 | 7 |
| 2017 | 12 |
| 2018 | 32 |
| 2019 | 8 |
| 2020 | 27 |
| 2021 | 4 |
| 2022 | 2 |
| 2023 | 0 |
| 2024 | 3 |
| 2025 | 4 |
| 2026 to date | 2 |
Rain
| Average year, 1991-2020 | 42.12 in |
| 12 months to August 2026 | 32.73 in (-9.39) |
| 2025 | 32.46 in (-9.66) |
| Wettest year since 1895 | 2018: 60.79 in |
| Driest year since 1895 | 1930: 20.40 in |
| Days with 1 inch or more, normal at WASHINGTON DC DULLES AP (17 mi away) | 11.4 |
Homes
| Housing units | 161,852 |
| Median year built | 1995 |
| Built before 1980 | 24% |
| Built 2000 or later | 41% |
| Owner-occupied | 74% |
| Median value, owner-occupied | $530,100 |
| Single-family detached | 55% |
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 |
|---|---|---|---|
| Manassas city, VA | 3 mi | 0% | 26% |
| Manassas Park city, VA | 5 mi | 0% | 16% |
| Fairfax County, VA | 14 mi | 6% | 33% |
| Fairfax city, VA | 14 mi | 2% | 10% |
| Fauquier County, VA | 19 mi | 6% | 28% |
| Stafford County, VA | 19 mi | 2% | 30% |
| Falls Church city, VA | 21 mi | 0% | 13% |
| Alexandria city, VA | 23 mi | 3% | 44% |
Sources: USDA SSURGO (September 5, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status