Frost Line Depth in Butte County, CA: Placer County Requires 18 in

No official local value

No official frost line depth is published for Butte County.

Nearby official codes require 18 in (1 verified code).

Source and how we checked

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

Climate: 7 nights a year at or below 32 °F (NOAA 1991–2020, Paradise, 6.2 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

18 in1 verified code within 63 mi
7nights a year at or below 32 °F
100%of nearby soil rated “none” for frost action (USDA)

Does Butte County have an official frost line depth?

No adopted frost line depth found for Butte County in its official documents (checked Oct 2026). The nearest official values, from codes we verified, are 18 in. Use the deepest of them until the building department confirms Butte County’s own number.

What frost line depth does Butte County use for footings under Table R301.2(1)? Is it 18 in, like Placer County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Butte County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 18 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 Butte County?

Drawn with the deepest nearby official value (18 in). Confirm Butte County’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

House or garage footing in Butte County: dig at least 18 in (46 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Using the nearby official value of 18 in until Butte County confirms its own
Project	Depth	Rule
House or garage footing	18 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	18 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	24 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	18 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 Butte County?

Butte County never averages a low below freezing. 7 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 39.9 °F.

NOAA 1991–2020 climate normals, Paradise station, 6.2 mi away, elevation 1,750 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	40.5	42	44.5	47.6	53.6	60.9	67	65.5	61.8	54.3	45.3	39.9
High	54.3	56.3	60.5	66	74.9	84.2	91.3	90.2	85.5	74.4	60.8	53.6

Butte County has more freezing nights than 122 of the 208 other California places we track. The California median is 3. Coldest: El Dorado County; mildest: San Diego.

What frost line depth do towns near Butte County use?

One official code near Butte County is verified.

Official frost line depths near Butte County
Place	Verified frost line	Distance
Placer County	18 in	63 mi away

How likely is the soil in Butte County to heave?

None 100%

USDA rates the sampled soil around Butte County as 100% none for frost action (main soils: Ultic Haploxeralfs, Lucksev, Xerorthents).

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

Butte County at a glance

Frost line depth: No official local value
Population (2023 est.): 207,172
Mean annual temperature: 61.4 °F
ZIP codes (21): 95901 · 95914 · 95916 · 95917 · 95926 · 95928 · 95929 · 95930 · 95938 · 95941 · 95942 · 95948 · 95954 · 95958 · 95965 · 95966 · 95968 · 95969 · 95973 · 95974 · 95978