Frost Line Depth in DeKalb County, IN: 36 in (Indiana rule)

State-set value

36in

91 cm · 3 ft

36 in (Indiana rule)

Set by the state: Indiana Residential Code Table R301.2(1), DeKalb County (state sets the whole design table).

Source and how we checked

DeKalb County does not publish its own value; the state rule applies.

Document: codes.iccsafe.org

Climate: 129 nights a year at or below 32 °F (NOAA 1991–2020, Garrett 1 S, 7.4 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

129nights a year at or below 32 °F
74%of nearby soil rated “high” for frost action (USDA)

How deep is the frost line in DeKalb County?

Indiana sets the frost footing depth for DeKalb County at 36 in (91 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 DeKalb County?

Indiana writes this depth into its statewide residential code, so DeKalb County’s building department enforces the state’s number rather than setting its own. See how Indiana sets frost line depth.

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

House or garage footing Deck footing Water service line Fence post

House or garage footing in DeKalb County: dig at least 36 in (91 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Minimum depths in DeKalb County with a 36 in frost line
Project	Depth	Rule
House or garage footing	36 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	36 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	42 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	36 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 DeKalb County?

Average lows are at or below freezing from Nov to Mar. 129 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 16.5 °F.

NOAA 1991–2020 climate normals, Garrett 1 S station, 7.4 mi away, elevation 870 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	16.5	18.6	26.9	36.7	47.7	57.3	60.3	58.4	51.2	40.8	30.8	21.9
High	30.2	34.2	45.8	59.2	69.8	77.5	80.8	78.8	73.4	61.2	46.8	34.6

DeKalb County has more freezing nights than 46 of the 55 other Indiana places we track. The Indiana median is 120. Coldest: LaGrange County; mildest: Evansville.

How likely is the soil in DeKalb County to heave?

Moderate 26%High 74%

USDA rates the sampled soil around DeKalb County as 26% moderate, 74% high for frost action (main soils: Blount, Pewamo, Sebewa).

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 DeKalb County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the DeKalb County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 36 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

DeKalb County at a glance

Frost line depth: 36 in (Indiana rule)
Population (2023 est.): 44,198
Mean annual temperature: 48.3 °F
ZIP codes (14): 46705 · 46706 · 46710 · 46721 · 46730 · 46738 · 46742 · 46747 · 46748 · 46755 · 46763 · 46785 · 46788 · 46793