Frost Line Depth in Sullivan County, Tennessee
- Tennessee range from verified codes
- Checked Oct 2026
No official local value
No official frost line depth is published for Sullivan County.
No verified code nearby; verified Tennessee codes range 5–13 in.
Source and how we checked
We searched this place’s own code and website and found no published frost line depth.
Climate: 94 nights a year at or below 32 °F (NOAA 1991–2020, Bristol Tri City Airport, 6.3 mi).
Checked Oct 2026. Report a correction
Does Sullivan County have an official frost line depth?
No adopted frost line depth found for Sullivan County in its official documents (checked Oct 2026). No verified code lies near Sullivan County; the Tennessee codes we verified range from 5 to 13 in. Ask the building department for Sullivan County’s own number before you dig.
What frost line depth does Sullivan County use for footings under Table R301.2(1)?
How deep do footings, decks and water lines need to be in Sullivan County?
Drawn with the deepest Tennessee official value (13 in). Confirm Sullivan County’s own depth before you dig.
House or garage footing in Sullivan County: dig at least 13 in (33 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 13 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 13 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 19 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 13 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 Sullivan County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
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- N
- D
Average lows are at or below freezing from Dec to Feb. 94 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 26.3 °F.
NOAA 1991–2020 climate normals, Bristol Tri City Airport station, 6.3 mi away, elevation 1,500 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 26.3 | 29.2 | 35.4 | 43.3 | 52.3 | 60.7 | 64.7 | 63.2 | 56.4 | 44.3 | 34.2 | 29.2 |
| High | 46.5 | 50.9 | 59.4 | 69.4 | 77.1 | 83.8 | 86.4 | 85.8 | 80.7 | 70.2 | 58.7 | 49.5 |
Sullivan County has more freezing nights than 46 of the 59 other Tennessee places we track. The Tennessee median is 84. Coldest: Greene County; mildest: Memphis.
How likely is the soil in Sullivan County to heave?
USDA rates the sampled soil around Sullivan County as 100% none for frost action (main soils: Collegedale, Etowah, Montevallo).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Sullivan County at a glance
- Frost line depth
- No official local value
- Population (2023 est.)
- 162,135
- Mean annual temperature
- 56.6 °F
- ZIP codes (12)
- 37617 · 37618 · 37620 · 37656 · 37659 · 37660 · 37663 · 37664 · 37665 · 37686 · 37694 · 37857