Council Bluffs, IA Frost Line Depth: 42 in

Verified

42in

107 cm · 3 ft 6 in

Set in the building code Council Bluffs has adopted.

Source and how we checked

Document: councilbluffs-ia.gov

Climate: 134 nights a year at or below 32 °F (NOAA 1991–2020, Omaha Eppley Airfield, 5.7 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

134nights a year at or below 32 °F
69%of nearby soil rated “high” for frost action (USDA)

How deep is the frost line in Council Bluffs?

Council Bluffs' building authority sets the frost line depth at 42 in (107 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 Council Bluffs?

Iowa leaves the frost line depth to each city or county, and Council Bluffs fills it in when it adopts the residential code. The value above comes from Council Bluffs’s own document on councilbluffs-ia.gov. See how Iowa sets frost line depth.

How deep do footings, decks and water lines need to be in Council Bluffs?

House or garage footing Deck footing Water service line Fence post

House or garage footing in Council Bluffs: dig at least 42 in (107 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Minimum depths in Council Bluffs with a 42 in frost line
Project	Depth	Rule
House or garage footing	42 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	42 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	48 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	42 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 Council Bluffs?

Average lows are at or below freezing from Nov to Mar. 134 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 15.2 °F.

NOAA 1991–2020 climate normals, Omaha Eppley Airfield station, 5.7 mi away, elevation 982 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	15.2	19.3	30	41.1	52.7	63.4	68	65.6	56.1	43.2	30.2	19.8
High	33.6	38.6	52.1	64.1	74.6	84.4	88.1	85.8	79.1	65.5	50.3	37.7

Council Bluffs has fewer freezing nights than 21 of the 28 other Iowa places we track. The Iowa median is 144. Coldest: Cerro Gordo County; mildest: Davenport.

How likely is the soil in Council Bluffs to heave?

Moderate 31%High 69%

USDA rates the sampled soil around Council Bluffs as 31% moderate, 69% high for frost action (main soils: Napier, Luton, Cooper).

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 Council Bluffs?

Call 811 (Iowa One Call) at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Council Bluffs building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 42 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Council Bluffs at a glance

Frost line depth: 42 in
County: Pottawattamie County
Population (2023 est.): 62,399
Mean annual temperature: 52.4 °F
ZIP codes (2): 51501 · 51503