Bannock County, ID Frost Line Depth: 36 in

Verified

36in

91 cm · 3 ft

Set in the building code Bannock County has adopted.

Source and how we checked

Document: bannockcounty.gov

Climate: 179 nights a year at or below 32 °F (NOAA 1991–2020, Mccammon, 3.3 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

0 of 1nearby verified codes use the same depth
179nights a year at or below 32 °F
59%of nearby soil rated “high” for frost action (USDA)

How deep is the frost line in Bannock County?

Bannock County's building authority sets the frost line depth 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 Bannock County?

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

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

House or garage footing Deck footing Water service line Fence post

House or garage footing in Bannock 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 Bannock 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 Bannock County?

Average lows are at or below freezing from Nov to Mar. 179 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 14.6 °F.

NOAA 1991–2020 climate normals, Mccammon station, 3.3 mi away, elevation 4,770 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	14.6	18.3	26.1	32.3	39.4	46	52	50.7	42.2	32.3	24	17.1
High	32.2	37.1	48.8	58.3	68	77	87.3	85.6	75.9	61.4	45.6	33.5

Bannock County has more freezing nights than 12 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 Bannock County use?

One official code near Bannock County is verified.

Official frost line depths near Bannock County
Place	Verified frost line	Distance
Bingham County	30 in	37 mi away

How likely is the soil in Bannock County to heave?

Moderate 41%High 59%

USDA rates the sampled soil around Bannock County as 41% moderate, 59% high for frost action (main soils: Ririe, Lanoak, Camelback).

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 Bannock County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Bannock 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.

Bannock County at a glance

Frost line depth: 36 in
Population (2023 est.): 90,400
Mean annual temperature: 46.1 °F
ZIP codes (10): 83201 · 83202 · 83204 · 83209 · 83214 · 83234 · 83245 · 83246 · 83250 · 83281