Frost Line Depth in Marion, IA: Nearby Codes Require 42 in

No official local value

No official frost line depth is published for Marion.

Nearby official codes require 42 in (2 verified codes).

Source and how we checked

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

Climate: 134 nights a year at or below 32 °F (NOAA 1991–2020, Cedar Rapids #1, 0.3 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

42 in2 verified codes within 7 mi
134nights a year at or below 32 °F
49%of nearby soil rated “moderate” for frost action (USDA)

Does Marion have an official frost line depth?

No adopted frost line depth found for Marion in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 42 in. Use the deepest of them until the building department confirms Marion’s own number.

What frost line depth does Marion use for footings under Table R301.2(1)? Is it 42 in, like Linn County?

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 Marion building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 42 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 Marion?

Drawn with the deepest nearby official value (42 in). Confirm Marion’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

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

Using the nearby official value of 42 in until Marion confirms its own
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 Marion?

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 12.5 °F.

NOAA 1991–2020 climate normals, Cedar Rapids #1 station, 0.3 mi away, elevation 813 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	12.5	16.6	27.5	38.4	49.6	59.6	63.3	61.2	53	41.5	29.3	18.6
High	30	35.1	48.9	63.3	73.8	82.3	85.5	83.4	77.3	64.1	48.1	34.7

Marion 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.

What frost line depth do towns near Marion use?

2 official codes near Marion are verified; each links to its document.

Official frost line depths near Marion
Place	Verified frost line	Distance
Linn County	42 in	2 mi away
Cedar Rapids	42 in	7 mi away

How likely is the soil in Marion to heave?

Moderate 49%High 45%

USDA rates the sampled soil around Marion as 5% low, 49% moderate, 45% high for frost action (main soils: Dickinson, Dinsdale, Klinger).

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

Marion at a glance

Frost line depth: No official local value
County: Linn County
Population (2023 est.): 42,213
Mean annual temperature: 49.9 °F
ZIP codes (3): 52302 · 52402 · 52403