Frost Line Depth in Los Angeles, California

Los Angeles’s adopted code
Checked Oct 2026
Sources

Verified

12in

30 cm · 1 ft

Set in the building code Los Angeles has adopted.

Source and how we checked

Document: up.codes

Climate: 1 night a year at or below 32 °F (NOAA 1991–2020, Culver City, 1 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

4 of 4nearby verified codes use the same depth
1nights a year at or below 32 °F
100%of nearby soil rated “none” for frost action (USDA)

How deep is the frost line in Los Angeles?

Los Angeles' building authority sets the frost line depth at 12 in (30 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 Los Angeles?

California leaves the frost line depth to each city or county, and Los Angeles fills it in when it adopts the residential code. The value above comes from Los Angeles’s own document on up.codes. See how California sets frost line depth.

How deep do footings, decks and water lines need to be in Los Angeles?

House or garage footing Deck footing Water service line Fence post

House or garage footing in Los Angeles: dig at least 12 in (30 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Minimum depths in Los Angeles with a 12 in frost line
Project	Depth	Rule
House or garage footing	12 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	12 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	18 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	12 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 Los Angeles?

Los Angeles never averages a low below freezing. 1 night a year reach 32 °F or colder; Dec is coldest, with an average low of 47.3 °F.

NOAA 1991–2020 climate normals, Culver City station, 1 mi away, elevation 92 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	48	48.5	50.8	53.1	56.6	60.3	63.1	63.6	62.2	57.9	51.9	47.3
High	66.6	66.5	68.2	70.8	72	74.7	78	79.1	78.4	75.8	70.6	65.9

Los Angeles has fewer freezing nights than 135 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 Los Angeles use?

4 official codes near Los Angeles are verified; each links to its document.

Official frost line depths near Los Angeles
Place	Verified frost line	Distance
Paramount	12 in	16 mi away
Norwalk	12 in	20 mi away
Whittier	12 in	23 mi away
Glendora	12 in	33 mi away

How likely is the soil in Los Angeles to heave?

None 100%

USDA rates the sampled soil around Los Angeles as 100% none for frost action (main soils: Anthraltic Xerorthents, Grommet, Pierview).

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 Los Angeles?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Los Angeles building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 12 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Los Angeles at a glance

Frost line depth: 12 in
County: Los Angeles County
Population (2023 est.): 3,820,914
Mean annual temperature: 63.8 °F
ZIP codes (142): 90001 · 90002 · 90003 · 90004 · 90005 · 90006 · 90007 · 90008 · 90010 · 90011 · 90012 · 90013 · 90014 · 90015 · 90016 · 90017 · 90018 · 90019 · 90020 · 90021 · 90023 · 90024 · 90025 · 90026 · 90027 · 90028 · 90029 · 90031 · 90032 · 90033 · 90034 · 90035 · 90036 · 90037 · 90038 · 90039 · 90041 · 90042 · 90043 · 90044 · 90045 · 90046 · 90047 · 90048 · 90049 · 90052 · 90056 · 90057 · 90058 · 90059 · 90061 · 90062 · 90063 · 90064 · 90065 · 90066 · 90067 · 90068 · 90069 · 90071 · 90077 · 90079 · 90089 · 90094 · 90095 · 90210 · 90211 · 90212 · 90230 · 90232 · 90247 · 90248 · 90272 · 90275 · 90280 · 90290 · 90291 · 90292 · 90293 · 90302 · 90304 · 90402 · 90403 · 90405 · 90501 · 90502 · 90710 · 90717 · 90731 · 90732 · 90744 · 90810 · 90813 · 91030 · 91040 · 91042 · 91105 · 91201 · 91206 · 91214 · 91302 · 91303 · 91304 · 91306 · 91307 · 91311 · 91316 · 91321 · 91324 · 91325 · 91326 · 91330 · 91331 · 91335 · 91340 · 91342 · 91343 · 91344 · 91345 · 91352 · 91356 · 91364 · 91367 · 91371 · 91401 · 91402 · 91403 · 91405 · 91406 · 91411 · 91423 · 91436 · 91504 · 91505 · 91506 · 91601 · 91602 · 91604 · 91605 · 91606 · 91607 · 91608