Frost Line Depth in Lake Stevens, Washington
- Lake Stevens’s adopted code
- Checked Oct 2026
- Sources
Verified
12in
30 cm · 1 ft
Set in the building code Lake Stevens has adopted.
Source and how we checked
Document: lakestevenswa.gov
Climate: 51 nights a year at or below 32 °F (NOAA 1991–2020, Everett, 4.9 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Lake Stevens?
Lake Stevens' building authority sets the frost line depth at 12 in (30 cm). Footings, piers and other permanent supports must reach at least this depth (IRC R403.1.4.1).
Who sets the frost line depth in Lake Stevens?
Washington leaves the frost line depth to each city or county, and Lake Stevens fills it in when it adopts the residential code. The value above comes from Lake Stevens’s own document on lakestevenswa.gov. Snohomish County, which covers the unincorporated land around Lake Stevens, uses 18 in, so check which one issues your permit. See how Washington sets frost line depth.
How deep do footings, decks and water lines need to be in Lake Stevens?
House or garage footing in Lake Stevens: dig at least 12 in (30 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 12 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 12 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 18 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 12 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 Lake Stevens?
- J
- F
- M
- A
- M
- J
- J
- A
- S
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- D
Lake Stevens never averages a low below freezing. 51 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 34.1 °F.
NOAA 1991–2020 climate normals, Everett station, 4.9 mi away, elevation 60 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 34.6 | 34.5 | 37.2 | 41.4 | 47 | 51.8 | 55.3 | 55.2 | 49.6 | 43.3 | 37.6 | 34.1 |
| High | 47.9 | 50.4 | 54.5 | 59.6 | 65.8 | 69.8 | 74.8 | 75.7 | 70.4 | 60.7 | 52.4 | 46.7 |
Lake Stevens has fewer freezing nights than 26 of the 47 other Washington places we track. The Washington median is 54. Coldest: Chelan County; mildest: Lakewood.
What frost line depth do towns near Lake Stevens use?
5 official codes near Lake Stevens are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Everett | 18 in | 5 mi away |
| Marysville | 18 in | 6 mi away |
| Lynnwood | 18 in | 15 mi away |
| Snohomish County | 18 in | 16 mi away |
| Redmond | 12 in | 23 mi away |
How likely is the soil in Lake Stevens to heave?
USDA rates the sampled soil around Lake Stevens as 100% none for frost action (main soils: Tokul, Mukilteo, Puget).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
How do you confirm the frost line before you dig in Lake Stevens?
Lake Stevens at a glance
- Frost line depth
- 12 in
- County
- Snohomish County
- Population (2023 est.)
- 40,521
- Mean annual temperature
- 52.1 °F
- ZIP codes (1)
- 98258