Frost Line Depth in Caldwell, ID: Nearby Codes Require 24 in

No official local value

No official frost line depth is published for Caldwell.

Nearby official codes require 24 in (3 verified codes).

Source and how we checked

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

Climate: 132 nights a year at or below 32 °F (NOAA 1991–2020, Nampa Sugar Factory, 5.1 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

24 in3 verified codes within 13 mi
132nights a year at or below 32 °F
67%of nearby soil rated “low” for frost action (USDA)

Does Caldwell have an official frost line depth?

No adopted frost line depth found for Caldwell in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 24 in. Use the deepest of them until the building department confirms Caldwell’s own number.

What frost line depth does Caldwell use for footings under Table R301.2(1)? Is it 24 in, like Canyon County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Caldwell building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 24 in (the deepest nearby 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 Caldwell?

Drawn with the deepest nearby official value (24 in). Confirm Caldwell’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

House or garage footing in Caldwell: dig at least 24 in (61 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Using the nearby official value of 24 in until Caldwell confirms its own
Project	Depth	Rule
House or garage footing	24 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	24 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	30 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	24 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 Caldwell?

Average lows are at or below freezing from Nov to Mar. 132 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 22.8 °F.

NOAA 1991–2020 climate normals, Nampa Sugar Factory station, 5.1 mi away, elevation 2,470 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	23	26	31.6	36.1	44	51	57.3	55.5	46.5	36.5	28.4	22.8
High	39.5	47.2	57.4	64.5	73.9	82.8	93.3	91.6	81	66.6	50.7	40

Caldwell has fewer freezing nights than 6 of the 13 other Idaho places we track. The Idaho median is 132. Coldest: Madison County; mildest: Canyon County.

What frost line depth do towns near Caldwell use?

3 official codes near Caldwell are verified; each links to its document.

Official frost line depths near Caldwell
Place	Verified frost line	Distance
Canyon County	24 in	3 mi away
Nampa	24 in	6 mi away
Meridian	24 in	13 mi away

How likely is the soil in Caldwell to heave?

Low 67%Moderate 22%

USDA rates the sampled soil around Caldwell as 67% low, 22% moderate, 11% high for frost action (main soils: Power, Bram, Oliaga).

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

Caldwell at a glance

Frost line depth: No official local value
County: Canyon County
Population (2023 est.): 68,336
Mean annual temperature: 52 °F
ZIP codes (4): 83605 · 83607 · 83651 · 83687