Frost Line Depth in Salt Lake County, Utah
- Salt Lake County’s adopted code
- Checked Oct 2026
- Sources
Verified
30in
76 cm · 2 ft 6 in
30 in (More at High Elevations)
Set in the building code Salt Lake County has adopted.
Source and how we checked
Document: msd.utah.gov
Climate: 81 nights a year at or below 32 °F (NOAA 1991–2020, Salt Lake Triad Ctr, 7.3 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Salt Lake County?
Salt Lake County's building authority sets the frost line depth at 30 in (76 cm); the district notes it may increase at higher elevations. Footings, piers and other permanent supports must reach at least this depth (IRC R403.1.4.1).
Who sets the frost line depth in Salt Lake County?
Utah leaves the frost line depth to each city or county, and Salt Lake County fills it in when it adopts the residential code. The value above comes from Salt Lake County’s own document on msd.utah.gov. See how Utah sets frost line depth.
How deep do footings, decks and water lines need to be in Salt Lake County?
House or garage footing in Salt Lake County: 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 Salt Lake County?
- J
- F
- M
- A
- M
- J
- J
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- S
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- N
- D
Average lows are at or below freezing from Dec to Feb. 81 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 27.6 °F.
NOAA 1991–2020 climate normals, Salt Lake Triad Ctr station, 7.3 mi away, elevation 4,280 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 27.6 | 31.4 | 38.7 | 44 | 52 | 60.5 | 69.9 | 67.9 | 58.2 | 46.6 | 36.6 | 28.3 |
| High | 39.7 | 45.8 | 55.8 | 62.1 | 72.3 | 82.7 | 91.4 | 89.7 | 79.8 | 65.9 | 51.7 | 40.5 |
Salt Lake County has fewer freezing nights than 23 of the 25 other Utah places we track. The Utah median is 118. Coldest: Summit County; mildest: St. George.
What frost line depth do towns near Salt Lake County use?
5 official codes near Salt Lake County are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Millcreek | 30 in | 5 mi away |
| West Jordan | 30 in | 6 mi away |
| South Jordan | 30 in | 8 mi away |
| Salt Lake City | 30 in | 8 mi away |
| Riverton | 30 in | 11 mi away |
How likely is the soil in Salt Lake County to heave?
USDA rates the sampled soil around Salt Lake County as 64% moderate, 36% high for frost action (main soils: Kidman, Bingham, Bramwell).
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 Salt Lake County?
Salt Lake County at a glance
- Frost line depth
- 30 in (More at High Elevations)
- Population (2023 est.)
- 1,185,813
- Mean annual temperature
- 55.8 °F
- ZIP codes (42)
- 84006 · 84009 · 84020 · 84044 · 84047 · 84065 · 84070 · 84081 · 84084 · 84088 · 84092 · 84093 · 84094 · 84095 · 84096 · 84101 · 84102 · 84103 · 84104 · 84105 · 84106 · 84107 · 84108 · 84109 · 84111 · 84112 · 84113 · 84114 · 84115 · 84116 · 84117 · 84118 · 84119 · 84120 · 84121 · 84123 · 84124 · 84128 · 84129 · 84138 · 84150 · 84180