Frost Line Depth in Davidson County, Tennessee

Davidson County’s adopted code
Checked Oct 2026
Sources

Verified

12in

30 cm · 1 ft

Set in the building code Davidson County has adopted.

Source and how we checked

Document: up.codes

Climate: 75 nights a year at or below 32 °F (NOAA 1991–2020, Shelby Bottoms Nature, 3.4 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

3 of 4nearby verified codes use the same depth
75nights a year at or below 32 °F
100%of nearby soil rated “none” for frost action (USDA)

How deep is the frost line in Davidson County?

Davidson County'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 Davidson County?

Tennessee leaves the frost line depth to each city or county, and Davidson County fills it in when it adopts the residential code. The value above comes from Davidson County’s own document on up.codes. See how Tennessee sets frost line depth.

How deep do footings, decks and water lines need to be in Davidson County?

House or garage footing Deck footing Water service line Fence post

House or garage footing in Davidson County: dig at least 12 in (30 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Minimum depths in Davidson County with a 12 in frost line
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 Davidson County?

Average lows are at or below freezing from Dec to Feb. 75 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 27.5 °F.

NOAA 1991–2020 climate normals, Shelby Bottoms Nature station, 3.4 mi away, elevation 405 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	27.5	31.2	38.6	47.4	55.7	63.9	67.9	67	59.3	47.2	36.7	31.7
High	48	52.2	61.9	72	79.9	86.7	89.3	88.6	83.6	73.2	61.6	51.1

Davidson County has fewer freezing nights than 43 of the 59 other Tennessee places we track. The Tennessee median is 84. Coldest: Greene County; mildest: Memphis.

What frost line depth do towns near Davidson County use?

4 official codes near Davidson County are verified; each links to its document.

Official frost line depths near Davidson County
Place	Verified frost line	Distance
Hendersonville	12 in	14 mi away
Cheatham County	12 in	19 mi away
Murfreesboro	12 in	30 mi away
Maury County	10 in	42 mi away

How likely is the soil in Davidson County to heave?

None 100%

USDA rates the sampled soil around Davidson County as 100% none for frost action (main soils: Maury, Urban land, Mimosa).

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 Davidson County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Davidson County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 12 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Davidson County at a glance

Frost line depth: 12 in
Population (2023 est.): 712,334
Mean annual temperature: 59.3 °F
ZIP codes (37): 37013 · 37015 · 37027 · 37064 · 37072 · 37076 · 37080 · 37086 · 37115 · 37122 · 37135 · 37138 · 37143 · 37189 · 37201 · 37203 · 37204 · 37205 · 37206 · 37207 · 37208 · 37209 · 37210 · 37211 · 37212 · 37213 · 37214 · 37215 · 37216 · 37217 · 37218 · 37219 · 37220 · 37221 · 37228 · 37232 · 37238