Frostline.info

Frost line depth in Orange County, California

Frost reaches about 0 inches in typical soil across Orange County. Codes in this climate commonly set footing depth at 12 inches (code minimum).

No meaningful frost
Estimated frost depth
0″
typical silt/loam soil
Typical code footing depth
12″ minimum
rule of thumb for this climate
Design freezing index
0
°F-days, 100-year winter
ZIP codes covered
89
#52 of 58 counties in CA (1 = deepest)
0″12″24″36″ ground
Est. frost (typical soil) Typical code footing depth Clay–sand range

Frost depth by soil type

Soil typeEst. frost depth
Sand / gravel (drains well)0″
Silt / loam (typical yard soil)0″
Clay (holds water)0″

County average. Methodology.

Verify before you dig. These are climate-based estimates. The legally required frost depth is the figure your building department publishes in its IRC Table R301.2 (climatic and geographic design criteria). Call the Orange County building or permitting office in California and call 811 before digging.

Frost depth by ZIP code in Orange County

ZIPCityEst. frostCode range
90620Buena Park0″12″ minimum
90621Buena Park0″12″ minimum
90623La Palma0″12″ minimum
90630Cypress0″12″ minimum
90631La Habra0″12″ minimum
90680Stanton0″12″ minimum
90720Los Alamitos0″12″ minimum
90740Seal Beach0″12″ minimum
92602Irvine0″12″ minimum
92603Irvine0″12″ minimum
92604Irvine0″12″ minimum
92606Irvine0″12″ minimum
92610Foothill Ranch0″12″ minimum
92612Irvine0″12″ minimum
92614Irvine0″12″ minimum
92617Irvine0″12″ minimum
92618Irvine0″12″ minimum
92620Irvine0″12″ minimum
92624Capistrano Beach0″12″ minimum
92625Corona Del Mar0″12″ minimum
92626Costa Mesa0″12″ minimum
92627Costa Mesa0″12″ minimum
92629Dana Point0″12″ minimum
92630Lake Forest0″12″ minimum
92637Laguna Woods0″12″ minimum
92646Huntington Beach0″12″ minimum
92647Huntington Beach0″12″ minimum
92648Huntington Beach0″12″ minimum
92649Huntington Beach0″12″ minimum
92651Laguna Beach0″12″ minimum
92653Laguna Hills0″12″ minimum
92655Midway City0″12″ minimum
92656Aliso Viejo0″12″ minimum
92657Newport Coast0″12″ minimum
92660Newport Beach0″12″ minimum
92661Newport Beach0″12″ minimum
92662Newport Beach0″12″ minimum
92663Newport Beach0″12″ minimum
92672San Clemente0″12″ minimum
92673San Clemente0″12″ minimum
92675San Juan Capistrano0″12″ minimum
92676Silverado0″12″ minimum
92677Laguna Niguel0″12″ minimum
92679Trabuco Canyon0″12″ minimum
92683Westminster0″12″ minimum
92688Rancho Santa Margarita0″12″ minimum
92691Mission Viejo0″12″ minimum
92692Mission Viejo0″12″ minimum
92694Ladera Ranch0″12″ minimum
92701Santa Ana0″12″ minimum
92703Santa Ana0″12″ minimum
92704Santa Ana0″12″ minimum
92705Santa Ana0″12″ minimum
92706Santa Ana0″12″ minimum
92707Santa Ana0″12″ minimum
92708Fountain Valley0″12″ minimum
92780Tustin0″12″ minimum
92782Tustin0″12″ minimum
92799Santa Ana0″12″ minimum
92801Anaheim0″12″ minimum
92802Anaheim0″12″ minimum
92804Anaheim0″12″ minimum
92805Anaheim0″12″ minimum
92806Anaheim0″12″ minimum
92807Anaheim0″12″ minimum
92808Anaheim0″12″ minimum
92809Anaheim0″12″ minimum
92821Brea0″12″ minimum
92823Brea0″12″ minimum
92831Fullerton0″12″ minimum
92832Fullerton0″12″ minimum
92833Fullerton0″12″ minimum
92835Fullerton0″12″ minimum
92840Garden Grove0″12″ minimum
92841Garden Grove0″12″ minimum
92843Garden Grove0″12″ minimum
92844Garden Grove0″12″ minimum
92845Garden Grove0″12″ minimum
92861Villa Park0″12″ minimum
92862Orange0″12″ minimum
92865Orange0″12″ minimum
92866Orange0″12″ minimum
92867Orange0″12″ minimum
92868Orange0″12″ minimum
92869Orange0″12″ minimum
92870Placentia0″12″ minimum
92886Yorba Linda0″12″ minimum
92887Yorba Linda0″12″ minimum
92899Anaheim0″12″ minimum

What this means for your project in Orange County

Deck footings & piers

Footings must bear below the frost line and at least 12″ below undisturbed ground. For planning in this area, budget for holes around 12″ deep until your permit office confirms the exact figure.

Fence posts

Set posts at least one-third of their above-ground height. Where frost heave is a problem, carry concrete footings below the frost line (about 12″ here in typical soil) and bell or taper the bottom.

Water & irrigation lines

Bury supply lines below the frost depth. Your water utility or plumbing code sets the minimum cover; freezing is rare, but exposed pipes still need insulation.

Slabs & frost-protected foundations

Frost-protected shallow foundations (IRC R403.3) use the 100-year air freezing index — 0 °F-days here — to size perimeter insulation, letting footings sit shallower than the frost line.

Weather stations used

NOAA weather stationDistance100-yr AFI
Santa Ana Fire Station, CA2 mi0
Tustin Irvine Ranch, CA4 mi0
Newport Beach Harbor, CA9 mi0
Yorba Linda, CA11 mi0

Nearby counties

Common questions

What is the frost line depth in Orange County?

About 0 inches in typical soil, based on NOAA's 100-year air freezing index. Across the county's ZIP codes the estimate runs from 0 to 0 inches.

How deep should footings be in Orange County, California?

Codes in climates like this commonly require 12 inches (code minimum). The Orange County building department publishes the required frost depth in its adopted code (IRC Table R301.2).

Does frost depth vary within Orange County?

Very little. Estimates across the county stay within 1 inches. Soil type matters more than location here.