Frost Line Depth in Dallas, Texas
- Dallas’s adopted code
- Checked Oct 2026
- Sources
Verified
6in
15 cm · 6 in
Set in the building code Dallas has adopted.
Footings still go at least 12 in (30 cm) below undisturbed ground (IRC R403.1.4).
Source and how we checked
Document: up.codes
Climate: 23 nights a year at or below 32 °F (NOAA 1991–2020, Dallas Love Fld, 6.6 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Dallas?
Dallas' building authority sets the frost line depth at 6 in (15 cm). Footings, piers and other permanent supports still go at least 12 in below undisturbed ground (IRC R403.1.4).
Who sets the frost line depth in Dallas?
Texas leaves the frost line depth to each city or county, and Dallas fills it in when it adopts the residential code. The value above comes from Dallas’s own document on up.codes. See how Texas sets frost line depth.
How deep do footings, decks and water lines need to be in Dallas?
House or garage footing in Dallas: 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 | 12 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 Dallas?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Dallas never averages a low below freezing. 23 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 37.9 °F.
NOAA 1991–2020 climate normals, Dallas Love Fld station, 6.6 mi away, elevation 440 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 37.9 | 41.9 | 49.4 | 56.8 | 66 | 73.8 | 77.7 | 77.4 | 70.1 | 58.7 | 47.8 | 39.8 |
| High | 57.7 | 62 | 69.9 | 77.4 | 84.9 | 92.7 | 96.9 | 97.1 | 90 | 79.5 | 67.8 | 59.2 |
Dallas has fewer freezing nights than 109 of the 168 other Texas places we track. The Texas median is 32. Coldest: Amarillo; mildest: Brownsville.
What frost line depth do towns near Dallas use?
5 official codes near Dallas are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Richardson | 6 in | 13 mi away |
| Lancaster | 6 in | 14 mi away |
| Lewisville | 6 in | 21 mi away |
| Allen | 6 in | 23 mi away |
| Frisco | 6 in | 25 mi away |
How likely is the soil in Dallas to heave?
USDA rates the sampled soil around Dallas as 100% none for frost action (main soils: Lewisville, Houston Black, Bastsil).
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 Dallas?
Dallas at a glance
- Frost line depth
- 6 in
- County
- Dallas County
- Population (2023 est.)
- 1,302,868
- Mean annual temperature
- 68 °F
- ZIP codes (81)
- 75001 · 75006 · 75007 · 75019 · 75032 · 75039 · 75041 · 75043 · 75051 · 75052 · 75061 · 75062 · 75063 · 75075 · 75080 · 75081 · 75087 · 75088 · 75089 · 75093 · 75098 · 75104 · 75126 · 75134 · 75141 · 75149 · 75150 · 75159 · 75166 · 75180 · 75182 · 75201 · 75202 · 75203 · 75204 · 75205 · 75206 · 75207 · 75208 · 75209 · 75210 · 75211 · 75212 · 75214 · 75215 · 75216 · 75217 · 75218 · 75219 · 75220 · 75223 · 75224 · 75225 · 75226 · 75227 · 75228 · 75229 · 75230 · 75231 · 75232 · 75233 · 75234 · 75235 · 75236 · 75237 · 75238 · 75240 · 75241 · 75243 · 75244 · 75246 · 75247 · 75248 · 75249 · 75251 · 75252 · 75253 · 75254 · 75270 · 75287 · 75390