Frost Line Depth in Bolingbrook, Illinois
- Bolingbrook’s adopted code
- Checked Oct 2026
- Sources
Verified
42in
107 cm · 3 ft 6 in
Set in the building code Bolingbrook has adopted.
Source and how we checked
Document: library.municode.com
Climate: 123 nights a year at or below 32 °F (NOAA 1991–2020, Romeoville Wfo, 5.9 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Bolingbrook?
Bolingbrook's 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 Bolingbrook?
Illinois leaves the frost line depth to each city or county, and Bolingbrook fills it in when it adopts the residential code. The value above comes from Bolingbrook’s own document on library.municode.com. Will County uses the same 42 in, so the depth does not change at the city limits. See how Illinois sets frost line depth.
How deep do footings, decks and water lines need to be in Bolingbrook?
House or garage footing in Bolingbrook: 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 Bolingbrook?
- J
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Average lows are at or below freezing from Nov to Mar. 123 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 16.1 °F.
NOAA 1991–2020 climate normals, Romeoville Wfo station, 5.9 mi away, elevation 660 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 16.1 | 19.7 | 29.7 | 39.6 | 50.3 | 60.3 | 64.5 | 63 | 55.4 | 43.5 | 31.9 | 22 |
| High | 31.7 | 36.3 | 48.5 | 61 | 72.4 | 81.5 | 84.7 | 82.7 | 76.4 | 63.8 | 48.9 | 36.8 |
Bolingbrook has fewer freezing nights than 40 of the 71 other Illinois places we track. The Illinois median is 127. Coldest: Hoffman Estates; mildest: Madison County.
What frost line depth do towns near Bolingbrook use?
5 official codes near Bolingbrook are verified; each links to its document.
| Place | Verified frost line | Distance |
|---|---|---|
| Naperville | 42 in | 5 mi away |
| Wheaton | 42 in | 12 mi away |
| Lombard | 42 in | 14 mi away |
| Hoffman Estates | 42 in | 26 mi away |
| Palatine | 42 in | 30 mi away |
How likely is the soil in Bolingbrook to heave?
USDA rates the sampled soil around Bolingbrook as 75% moderate, 25% high for frost action (main soils: Ozaukee, Warsaw, Brenton).
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 Bolingbrook?
Bolingbrook at a glance
- Frost line depth
- 42 in
- County
- Will County
- Population (2023 est.)
- 74,088
- Mean annual temperature
- 50.9 °F
- ZIP codes (6)
- 60440 · 60490 · 60517 · 60544 · 60565 · 60585