Frost Line Depth in Houston, Texas

Houston’s adopted code
Checked Oct 2026
Sources

Verified

6in

15 cm · 6 in

Set in the building code Houston has adopted.

Footings still go at least 12 in (30 cm) below undisturbed ground (IRC R403.1.4).

Source and how we checked

Document: houstontx.gov

Climate: 5 nights a year at or below 32 °F (NOAA 1991–2020, Houston-Port, 7.1 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

0 of 1nearby verified codes use the same depth
5nights a year at or below 32 °F
100%of nearby soil rated “none” for frost action (USDA)

How deep is the frost line in Houston?

"{confirmed quote}". Footings, piers and other permanent supports still go at least 12 in below undisturbed ground (IRC R403.1.4).

Who sets the frost line depth in Houston?

Texas leaves the frost line depth to each city or county, and Houston fills it in when it adopts the residential code. The value above comes from Houston’s own document on houstontx.gov. See how Texas sets frost line depth.

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

House or garage footing Deck footing Water service line Fence post

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

Minimum depths in Houston with a 6 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	12 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 Houston?

Houston never averages a low below freezing. 5 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 44.3 °F.

NOAA 1991–2020 climate normals, Houston-Port station, 7.1 mi away, elevation 19 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	44.3	48.9	53.7	60.9	68.7	74.8	76.8	76.8	71.8	62.7	52.9	46
High	62.8	66.7	73.3	79.2	85.7	91.3	93.2	94.3	89.8	81.9	72	65.2

Houston has fewer freezing nights than 152 of the 168 other Texas places we track. The Texas median is 32. Coldest: Amarillo; mildest: Brownsville.

What frost line depth do towns near Houston use?

One official code near Houston is verified.

Official frost line depths near Houston
Place	Verified frost line	Distance
Missouri City	12 in	18 mi away

How likely is the soil in Houston to heave?

None 100%

USDA rates the sampled soil around Houston as 100% none for frost action (main soils: Aris, Bernard, Mocarey).

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 Houston?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Houston building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 6 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Houston at a glance

Frost line depth: 6 in
County: Harris County
Population (2023 est.): 2,314,157
Mean annual temperature: 70.6 °F
ZIP codes (140): 77002 · 77003 · 77004 · 77005 · 77006 · 77007 · 77008 · 77009 · 77010 · 77011 · 77012 · 77013 · 77014 · 77015 · 77016 · 77017 · 77018 · 77019 · 77020 · 77021 · 77022 · 77023 · 77024 · 77025 · 77026 · 77027 · 77028 · 77029 · 77030 · 77031 · 77032 · 77033 · 77034 · 77035 · 77036 · 77037 · 77038 · 77039 · 77040 · 77041 · 77042 · 77043 · 77044 · 77045 · 77046 · 77047 · 77048 · 77049 · 77050 · 77051 · 77053 · 77054 · 77055 · 77056 · 77057 · 77058 · 77059 · 77060 · 77061 · 77062 · 77063 · 77064 · 77065 · 77066 · 77067 · 77068 · 77069 · 77070 · 77071 · 77072 · 77073 · 77074 · 77075 · 77076 · 77077 · 77078 · 77079 · 77080 · 77081 · 77082 · 77083 · 77084 · 77085 · 77086 · 77087 · 77088 · 77089 · 77090 · 77091 · 77092 · 77093 · 77094 · 77095 · 77096 · 77098 · 77099 · 77204 · 77336 · 77338 · 77339 · 77345 · 77346 · 77357 · 77365 · 77373 · 77375 · 77377 · 77379 · 77380 · 77386 · 77388 · 77389 · 77396 · 77401 · 77406 · 77407 · 77429 · 77433 · 77441 · 77447 · 77449 · 77450 · 77477 · 77484 · 77489 · 77493 · 77494 · 77498 · 77504 · 77505 · 77506 · 77520 · 77530 · 77532 · 77545 · 77546 · 77547 · 77571 · 77587 · 77598