Frost Line Depth in Austin, Texas
- Austin’s adopted code
- Checked Oct 2026
- Sources
Verified
12in
30 cm · 1 ft
Set in the building code Austin has adopted.
Source and how we checked
Document: services.austintexas.gov
Climate: 12 nights a year at or below 32 °F (NOAA 1991–2020, Austin-Camp Mabry, 1.6 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Austin?
Austin's 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 Austin?
Texas leaves the frost line depth to each city or county, and Austin fills it in when it adopts the residential code. The value above comes from Austin’s own document on services.austintexas.gov. See how Texas sets frost line depth.
How deep do footings, decks and water lines need to be in Austin?
House or garage footing in Austin: 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 Austin?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Austin never averages a low below freezing. 12 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 41.8 °F.
NOAA 1991–2020 climate normals, Austin-Camp Mabry station, 1.6 mi away, elevation 670 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 41.8 | 45.8 | 52.2 | 58.9 | 66.8 | 72.9 | 75 | 75.1 | 70.1 | 60.8 | 50.5 | 43.4 |
| High | 62.5 | 66.5 | 73.3 | 80.3 | 86.9 | 93.2 | 96.6 | 97.8 | 91.4 | 82.5 | 71.5 | 63.9 |
Austin has fewer freezing nights than 129 of the 168 other Texas places we track. The Texas median is 32. Coldest: Amarillo; mildest: Brownsville.
What frost line depth do towns near Austin use?
3 official codes near Austin are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Cedar Park | 6 in | 15 mi away |
| Leander | 6 in | 20 mi away |
| Kyle | 6 in | 22 mi away |
How likely is the soil in Austin to heave?
USDA rates the sampled soil around Austin as 100% none for frost action (main soils: Austin, Brackett, Eckrant).
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 Austin?
Austin at a glance
- Frost line depth
- 12 in
- County
- Travis County
- Population (2023 est.)
- 979,882
- Mean annual temperature
- 70 °F
- ZIP codes (53)
- 78610 · 78612 · 78613 · 78617 · 78641 · 78652 · 78653 · 78660 · 78681 · 78701 · 78702 · 78703 · 78704 · 78705 · 78712 · 78717 · 78719 · 78721 · 78722 · 78723 · 78724 · 78725 · 78726 · 78727 · 78728 · 78729 · 78730 · 78731 · 78732 · 78733 · 78734 · 78735 · 78736 · 78737 · 78738 · 78739 · 78741 · 78742 · 78744 · 78745 · 78746 · 78747 · 78748 · 78749 · 78750 · 78751 · 78752 · 78753 · 78754 · 78756 · 78757 · 78758 · 78759