Frost Line Depth in St. Charles Parish, LA: Frost Rarely Reaches the Ground

No official local value

Frost rarely reaches the ground in St. Charles Parish.

No verified code nearby. The only verified Louisiana code we read, Jefferson Parish’s, uses 12 in.

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

Source and how we checked

We searched this place’s own code and website and found no published frost line depth.

Climate: 5 nights a year at or below 32 °F (NOAA 1991–2020, New Orleans International Airport, 8.8 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

12 inJefferson Parish, the only verified Louisiana code
5nights a year at or below 32 °F
100%of nearby soil rated “none” for frost action (USDA)

Does St. Charles Parish have an official frost line depth?

No adopted frost line depth found for St. Charles Parish in its official documents (checked Oct 2026). No verified code lies near St. Charles Parish; the only Louisiana code we verified, Jefferson Parish’s, uses 12 in. Ask the building department for St. Charles Parish’s own number before you dig.

What frost line depth does St. Charles Parish use for footings under Table R301.2(1)?

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

How deep do footings, decks and water lines need to be in St. Charles Parish?

Drawn with the deepest Louisiana official value (12 in). Confirm St. Charles Parish’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

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

Minimum depths in St. Charles Parish 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 St. Charles Parish?

St. Charles Parish never averages a low below freezing. 5 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 46.1 °F.

NOAA 1991–2020 climate normals, New Orleans International Airport station, 8.8 mi away, elevation 4 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	46.1	49.7	55.3	61.7	69	74.7	76.5	76.6	73.5	64.3	53.7	48.4
High	62.5	66.4	72.3	78.5	85.3	90	91.4	91.3	88.1	80.6	71.2	64.8

St. Charles Parish has fewer freezing nights than 29 of the 33 other Louisiana places we track. The Louisiana median is 18. Coldest: Lincoln Parish; mildest: New Orleans.

How likely is the soil in St. Charles Parish to heave?

None 100%

USDA rates the sampled soil around St. Charles Parish as 100% none for frost action (main soils: Barbary, Cancienne, Thibaut).

USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.

St. Charles Parish at a glance

Frost line depth: No official local value
Population (2023 est.): 50,620
Mean annual temperature: 70.5 °F
ZIP codes (10): 70030 · 70031 · 70039 · 70047 · 70057 · 70068 · 70070 · 70079 · 70080 · 70087