Frost Line Depth in Arlington County, Virginia
- 3 verified codes nearby
- Checked Oct 2026
No official local value
No official frost line depth is published for Arlington County.
Nearby official codes require 18–24 in (3 verified codes).
Source and how we checked
We searched this place’s own code and website and found no published frost line depth.
Climate: 60 nights a year at or below 32 °F (NOAA 1991–2020, Washington Reagan Airport, 4.1 mi).
Checked Oct 2026. Report a correction
Does Arlington County have an official frost line depth?
No adopted frost line depth found for Arlington County in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 18 to 24 in. Use the deepest of them until the building department confirms Arlington County’s own number.
What frost line depth does Arlington County use for footings under Table R301.2(1)? Is it 24 in, like Alexandria?
How deep do footings, decks and water lines need to be in Arlington County?
Drawn with the deepest nearby official value (24 in). Confirm Arlington County’s own depth before you dig.
House or garage footing in Arlington County: dig at least 24 in (61 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 24 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 24 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 30 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 24 in | No code rule; common practice is below the frost line |
Work out posts, concrete and footing sizes with the fence post depth calculator or the deck footing calculator.
How cold does it get in Arlington County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Average lows are at or below freezing from Jan to Feb. 60 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 30.1 °F.
NOAA 1991–2020 climate normals, Washington Reagan Airport station, 4.1 mi away, elevation 10 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 30.1 | 31.8 | 38.6 | 48.4 | 58 | 67.5 | 72.4 | 71 | 64.1 | 52.2 | 41.6 | 34.5 |
| High | 44.8 | 48.3 | 56.5 | 68 | 76.5 | 85.1 | 89.6 | 87.8 | 80.7 | 69.4 | 58.2 | 48.8 |
Arlington County has fewer freezing nights than 16 of the 22 other Virginia places we track. The Virginia median is 94. Coldest: Shenandoah County; mildest: Norfolk.
What frost line depth do towns near Arlington County use?
3 official codes near Arlington County are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Alexandria | 24 in | 4 mi away |
| Fairfax County | 24 in | 10 mi away |
| Spotsylvania County | 18 in | 57 mi away |
How likely is the soil in Arlington County to heave?
USDA rates the sampled soil around Arlington County as 57% none, 1% low, 34% moderate, 8% high for frost action (main soils: Urban land, Arlington National Cemetery, Glenelg).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Arlington County at a glance
- Frost line depth
- No official local value
- Population (2023 est.)
- 234,162
- Mean annual temperature
- 59.3 °F
- ZIP codes (12)
- 22101 · 22201 · 22202 · 22203 · 22204 · 22205 · 22206 · 22207 · 22209 · 22211 · 22213 · 22214