How deep do footings need to be for frost?

TexasReviewed October 2026

It depends on where you are, and your local code sets the number. IRC-based codes put footings at least 12 inches below undisturbed ground, and deeper where the ground freezes, with each jurisdiction listing its own frost line in its climate table. Texas examples show how much this varies: North Central Texas regional IRC amendments list a frost line of 6 inches, while Amarillo's amendments list 18 inches. Bullhead City, Arizona lists zero. Northern states commonly require far deeper footings. Frost heave can lift shallow footings and rack a home out of level, so call your city or county building department for the local frost depth before digging piers or footings.

Check your local rule. This varies by state, county or city. Your permitting office has the final word; the official lookup pages below show you who that is.

Sources

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General information, written in our own words from the sources listed with each answer. It is not legal, engineering, tax or financial advice. Rules change and differ by state, county and city, so confirm with the office that issues your permit before you build. Last reviewed October 2026.