Frost Line Depth in Whiteside County, IL: Nearby Codes Require 42 in

No official local value

No official frost line depth is published for Whiteside County.

Nearby official codes require 42 in (3 verified codes).

Source and how we checked

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

Climate: 145 nights a year at or below 32 °F (NOAA 1991–2020, Morrison, 4.2 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

42 in3 verified codes within 67 mi
145nights a year at or below 32 °F
80%of nearby soil rated “high” for frost action (USDA)

Does Whiteside County have an official frost line depth?

No adopted frost line depth found for Whiteside 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 Whiteside County’s own number.

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

Call 811 (JULIE) at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Whiteside County 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 Whiteside County?

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

House or garage footing Deck footing Water service line Fence post

House or garage footing in Whiteside County: 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 Whiteside County 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 Whiteside County?

Average lows are at or below freezing from Nov to Mar. 145 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 12 °F.

NOAA 1991–2020 climate normals, Morrison station, 4.2 mi away, elevation 632 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	12	15.7	26.7	36.9	48.8	58.6	62	59.7	51.2	39.4	28.4	18.3
High	28.9	33.6	46.2	59.5	70.8	79.9	83.1	81.1	75	62.2	47.2	34.5

Whiteside County has more freezing nights than 67 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 Whiteside County use?

3 official codes near Whiteside County are verified; each links to its document.

Official frost line depths near Whiteside County
Place	Verified frost line	Distance
Rockford	42 in	56 mi away
LaSalle County	42 in	60 mi away
Peoria County	42 in	67 mi away

How likely is the soil in Whiteside County to heave?

Moderate 20%High 80%

USDA rates the sampled soil around Whiteside County as 20% moderate, 80% high for frost action (main soils: Richwood, Elburn, Drummer).

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

Whiteside County at a glance

Frost line depth: No official local value
Population (2023 est.): 54,498
Mean annual temperature: 48.3 °F
ZIP codes (15): 61014 · 61037 · 61064 · 61071 · 61081 · 61230 · 61243 · 61250 · 61251 · 61252 · 61254 · 61261 · 61270 · 61277 · 61283