Frost Line Depth in Black Hawk County, Iowa
- 2 verified codes nearby
- Checked Oct 2026
No official local value
No official frost line depth is published for Black Hawk County.
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: 150 nights a year at or below 32 °F (NOAA 1991–2020, Waterloo Municipal Airport, 7.5 mi).
Checked Oct 2026. Report a correction
Does Black Hawk County have an official frost line depth?
No adopted frost line depth found for Black Hawk County 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 Black Hawk County’s own number.
What frost line depth does Black Hawk County use for footings under Table R301.2(1)? Is it 42 in, like Linn County?
How deep do footings, decks and water lines need to be in Black Hawk County?
Drawn with the deepest nearby official value (42 in). Confirm Black Hawk County’s own depth before you dig.
House or garage footing in Black Hawk County: dig at least 42 in (107 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| 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 Black Hawk County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
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- N
- D
Average lows are at or below freezing from Nov to Mar. 150 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 10.7 °F.
NOAA 1991–2020 climate normals, Waterloo Municipal Airport station, 7.5 mi away, elevation 868 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 10.7 | 15.2 | 26.9 | 37.9 | 50.2 | 60.8 | 64 | 61 | 52.4 | 40.2 | 27.7 | 17 |
| High | 28.2 | 32.6 | 46.5 | 60.9 | 72.8 | 82.2 | 85 | 82.9 | 76.8 | 63 | 47.1 | 33.7 |
Black Hawk County has more freezing nights than 17 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 Black Hawk County use?
2 official codes near Black Hawk County are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Linn County | 42 in | 45 mi away |
| Cedar Rapids | 42 in | 47 mi away |
How likely is the soil in Black Hawk County to heave?
USDA rates the sampled soil around Black Hawk County as 38% low, 13% moderate, 49% high for frost action (main soils: Finchford, Clyde, Flagler).
USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.
Black Hawk County at a glance
- Frost line depth
- No official local value
- Population (2023 est.)
- 130,471
- Mean annual temperature
- 49 °F
- ZIP codes (18)
- 50612 · 50613 · 50623 · 50626 · 50629 · 50634 · 50643 · 50647 · 50648 · 50651 · 50667 · 50669 · 50670 · 50675 · 50701 · 50702 · 50703 · 50707