Frost Line Depth in Grand Forks County, ND: North Dakota Codes Require 48 in

No official local value

No official frost line depth is published for Grand Forks County.

No verified code nearby; every verified North Dakota code we read uses 48 in.

Source and how we checked

We searched this place’s own code and website and found no published frost line depth.

Climate: 185 nights a year at or below 32 °F (NOAA 1991–2020, Grand Forks International Airport, 12.4 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

48 inused by every verified North Dakota code
185nights a year at or below 32 °F
78%of nearby soil rated “high” for frost action (USDA)

Does Grand Forks County have an official frost line depth?

No adopted frost line depth found for Grand Forks County in its official documents (checked Oct 2026). No verified code lies near Grand Forks County; every North Dakota code we verified uses 48 in. Ask the building department for Grand Forks County’s own number before you dig.

What frost line depth does Grand Forks County use for footings under Table R301.2(1)?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Grand Forks County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 48 in (the deepest verified state value) unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

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

Drawn with the deepest North Dakota official value (48 in). Confirm Grand Forks County’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

House or garage footing in Grand Forks County: dig at least 48 in (122 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Using the nearby official value of 48 in until Grand Forks County confirms its own
Project	Depth	Rule
House or garage footing	48 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	48 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	54 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	48 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 Grand Forks County?

Average lows are at or below freezing from Nov to Apr. 185 nights a year reach 32 °F or colder; Jan is coldest, with an average low of -3.1 °F.

NOAA 1991–2020 climate normals, Grand Forks International Airport station, 12.4 mi away, elevation 842 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	-3.1	0.7	15	29.3	41.4	52.9	57	54.3	45.3	32.5	17.8	4.2
High	15.8	20.5	33.9	52	66.9	76.4	80.7	79.8	70.4	53.9	35.7	21.4

How likely is the soil in Grand Forks County to heave?

Low 13%High 78%

USDA rates the sampled soil around Grand Forks County as 13% low, 9% moderate, 78% high for frost action (main soils: Gilby, Antler, Arveson).

USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.

Grand Forks County at a glance

Frost line depth: No official local value
Population (2023 est.): 72,708
Mean annual temperature: 39.8 °F
ZIP codes (22): 56744 · 58201 · 58202 · 58203 · 58204 · 58205 · 58212 · 58214 · 58228 · 58231 · 58233 · 58235 · 58240 · 58244 · 58251 · 58256 · 58258 · 58261 · 58266 · 58267 · 58275 · 58278