Nevada County, CA Frost Line Depth: 18 in

Verified

18in

46 cm · 1 ft 6 in

Set in the building code Nevada County has adopted.

Source and how we checked

Document: library.municode.com

Climate: 79 nights a year at or below 32 °F (NOAA 1991–2020, Blue Canyon Airport, 3.5 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

1 of 1nearby verified codes use the same depth
79nights a year at or below 32 °F
71%of nearby soil rated “low” for frost action (USDA)

How deep is the frost line in Nevada County?

Nevada County's building authority sets the frost line depth at 18 in (46 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 Nevada County?

California leaves the frost line depth to each city or county, and Nevada County fills it in when it adopts the residential code. The value above comes from Nevada County’s own document on library.municode.com. See how California sets frost line depth.

How deep do footings, decks and water lines need to be in Nevada County?

House or garage footing Deck footing Water service line Fence post

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

Minimum depths in Nevada County with a 18 in frost line
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 Nevada County?

Nevada County never averages a low below freezing. 79 nights a year reach 32 °F or colder; Feb is coldest, with an average low of 33.1 °F.

NOAA 1991–2020 climate normals, Blue Canyon Airport station, 3.5 mi away, elevation 5,276 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	34.4	33.1	34.7	37.5	45.6	54.4	62.7	62.1	57.2	48.1	39	33.6
High	46.5	45	48.2	52	60.6	69.8	77.8	77.4	72.9	62.9	51.2	44.8

Nevada County has more freezing nights than 205 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 Nevada County use?

One official code near Nevada County is verified.

Official frost line depths near Nevada County
Place	Verified frost line	Distance
Placer County	18 in	16 mi away

How likely is the soil in Nevada County to heave?

Low 71%Moderate 20%

USDA rates the sampled soil around Nevada County as 10% none, 71% low, 20% moderate for frost action (main soils: Hurlbut, McCarthy, Crozier).

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 Nevada County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Nevada County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 18 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Nevada County at a glance

Frost line depth: 18 in
Population (2023 est.): 102,037
Mean annual temperature: 52.1 °F
ZIP codes (12): 95602 · 95728 · 95945 · 95946 · 95949 · 95959 · 95960 · 95975 · 95977 · 95986 · 96111 · 96161