Santa Ana, CA Frost Line Depth: 12

Verified

12in

30 cm · 1 ft

12–24 in

Set in the building code Santa Ana has adopted.

Source and how we checked

Document: santa-ana.gov

Climate: 0 nights a year at or below 32 °F (NOAA 1991–2020, Santa Ana Fire Stn, 1.1 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

3 of 3nearby verified codes use the same depth
0nights a year at or below 32 °F
100%of nearby soil rated “none” for frost action (USDA)

How deep is the frost line in Santa Ana?

Santa Ana's building authority lists a frost line depth of 12–24 in (30–61 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 Santa Ana?

California leaves the frost line depth to each city or county, and Santa Ana fills it in when it adopts the residential code. The value above comes from Santa Ana’s own document on santa-ana.gov. See how California sets frost line depth.

How deep do footings, decks and water lines need to be in Santa Ana?

House or garage footing Deck footing Water service line Fence post

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

Minimum depths in Santa Ana 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 Santa Ana?

Santa Ana never averages a low below freezing. 0 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 48.1 °F.

NOAA 1991–2020 climate normals, Santa Ana Fire Stn station, 1.1 mi away, elevation 135 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	48.7	49.5	51.8	54.2	58.1	61.3	64.7	65.3	63.9	59.4	52.8	48.1
High	69.3	69.3	71.2	73.2	74.7	77.7	82.5	84.6	83.8	79.4	74	68.4

Santa Ana has fewer freezing nights than 166 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 Santa Ana use?

3 official codes near Santa Ana are verified; each links to its document.

Official frost line depths near Santa Ana
Place	Verified frost line	Distance
Mission Viejo	12 in	16 mi away
Norwalk	12 in	17 mi away
Whittier	12 in	18 mi away

How likely is the soil in Santa Ana to heave?

None 100%

USDA rates the sampled soil around Santa Ana as 100% none for frost action (main soils: San Emigdio, Metz, Chino).

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 Santa Ana?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Santa Ana 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.

Santa Ana at a glance

Frost line depth: 12–24 in
County: Orange County
Population (2023 est.): 310,539
Mean annual temperature: 66.1 °F
ZIP codes (10): 92626 · 92701 · 92703 · 92704 · 92705 · 92706 · 92707 · 92780 · 92866 · 92868