Frost Line Depth in Petaluma, California
- 3 verified codes nearby
- Checked Oct 2026
No official local value
No official frost line depth is published for Petaluma.
Nearby official codes require 5–30 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: 21 nights a year at or below 32 °F (NOAA 1991–2020, Petaluma Airport, 1.6 mi).
Checked Oct 2026. Report a correction
Does Petaluma have an official frost line depth?
No adopted frost line depth found for Petaluma in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 5 to 30 in. Use the deepest of them until the building department confirms Petaluma’s own number.
What frost line depth does Petaluma use for footings under Table R301.2(1)? Is it 30 in, like Brentwood?
How deep do footings, decks and water lines need to be in Petaluma?
Drawn with the deepest nearby official value (30 in). Confirm Petaluma’s own depth before you dig.
House or garage footing in Petaluma: 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 Petaluma?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Petaluma never averages a low below freezing. 21 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 38.4 °F.
NOAA 1991–2020 climate normals, Petaluma Airport station, 1.6 mi away, elevation 20 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 39 | 40.4 | 41.9 | 43.8 | 47.4 | 50.4 | 52.4 | 52.8 | 51.4 | 47.6 | 42.3 | 38.4 |
| High | 57.6 | 61.3 | 64.5 | 67.8 | 71.9 | 78.1 | 80.8 | 81.2 | 81.6 | 76.4 | 65.5 | 57.9 |
Petaluma has more freezing nights than 182 of the 208 other California places we track. The California median is 3. Coldest: El Dorado County; mildest: San Diego.
What frost line depth do towns near Petaluma use?
3 official codes near Petaluma are verified; each links to its document.
How likely is the soil in Petaluma to heave?
USDA rates the sampled soil around Petaluma as 100% none for frost action (main soils: Clear Lake, Cotati, Reyes).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Petaluma at a glance
- Frost line depth
- No official local value
- County
- Sonoma County
- Population (2023 est.)
- 58,800
- Mean annual temperature
- 58 °F
- ZIP codes (2)
- 94952 · 94954