Frost Line Depth in Gaithersburg, Maryland
- 4 verified codes nearby
- Checked Oct 2026
No official local value
No official frost line depth is published for Gaithersburg.
Nearby official codes require 24–30 in (4 verified codes).
Source and how we checked
We searched this place’s own code and website and found no published frost line depth.
Climate: 86 nights a year at or below 32 °F (NOAA 1991–2020, Rockville 1 Ne, 4.1 mi).
Checked Oct 2026. Report a correction
Does Gaithersburg have an official frost line depth?
No adopted frost line depth found for Gaithersburg in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 24 to 30 in. Use the deepest of them until the building department confirms Gaithersburg’s own number.
What frost line depth does Gaithersburg use for footings under Table R301.2(1)? Is it 30 in, like Howard County?
How deep do footings, decks and water lines need to be in Gaithersburg?
Drawn with the deepest nearby official value (30 in). Confirm Gaithersburg’s own depth before you dig.
House or garage footing in Gaithersburg: dig at least 30 in (76 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 30 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 30 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 36 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 30 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 Gaithersburg?
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Average lows are at or below freezing from Dec to Feb. 86 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 26.9 °F.
NOAA 1991–2020 climate normals, Rockville 1 Ne station, 4.1 mi away, elevation 440 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 26.9 | 28.4 | 35.9 | 45.6 | 54.9 | 63.6 | 68.8 | 67 | 60 | 48 | 38.2 | 30.9 |
| High | 42.2 | 45 | 53.7 | 65.9 | 74.3 | 82.2 | 87.1 | 84.9 | 77.5 | 65.9 | 55.7 | 46 |
Gaithersburg has fewer freezing nights than 6 of the 6 other Maryland places we track. The Maryland median is 98. Coldest: Bowie; mildest: Gaithersburg.
What frost line depth do towns near Gaithersburg use?
4 official codes near Gaithersburg are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Howard County | 30 in | 16 mi away |
| Frederick County | 30 in | 25 mi away |
| Baltimore | 30 in | 33 mi away |
| Calvert County | 24 in | 56 mi away |
How likely is the soil in Gaithersburg to heave?
USDA rates the sampled soil around Gaithersburg as 80% moderate, 20% high for frost action (main soils: Glenelg, Glenville, Hatboro).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Gaithersburg at a glance
- Frost line depth
- No official local value
- County
- Montgomery County
- Population (2023 est.)
- 69,563
- Mean annual temperature
- 56.2 °F
- ZIP codes (5)
- 20877 · 20878 · 20879 · 20886 · 20899