Frost Line Depth in Largo, FL: No Frost Line, 12 in Minimum

State-set value

No Frost Line, 12 in Minimum

Florida Building Code–Residential: no frost line (Table R301.2 'Reserved'); 12-in footing minimum, R403.1.4.

Source and how we checked

Largo does not publish its own value; the state rule applies.

Document: up.codes

Climate: 0 nights a year at or below 32 °F (NOAA 1991–2020, St Petersburg International Airport, 4.9 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

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 Largo?

Florida's building code sets no frost line; footings must still be at least 12 in (30 cm) below undisturbed ground.

Who sets the frost line depth in Largo?

Florida writes this depth into its statewide residential code, so Largo’s building department enforces the state’s number rather than setting its own. Pinellas County uses the same 12 in, so the depth does not change at the city limits. See how Florida sets frost line depth.

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

House or garage footing Deck footing Water service line Fence post

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

Minimum depths in Largo 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 Largo?

Largo never averages a low below freezing. 0 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 52.5 °F.

NOAA 1991–2020 climate normals, St Petersburg International Airport station, 4.9 mi away, elevation 11 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	52.5	55.1	59.2	64.2	69.8	74.6	75.9	76.3	75.2	69.7	60.9	56
High	70.6	73.3	77	81.8	87.1	89.6	90.3	90.6	88.9	84.2	77.2	72.8

Largo has fewer freezing nights than 68 of the 110 other Florida places we track. The Florida median is 1. Coldest: Okaloosa County; mildest: Port St. Lucie.

How likely is the soil in Largo to heave?

None 100%

USDA rates the sampled soil around Largo as 100% none for frost action (main soils: Myakka, Wulfert, EauGallie).

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 Largo?

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

Largo at a glance

Frost line depth: No Frost Line, 12 in Minimum
County: Pinellas County
Population (2023 est.): 82,248
Mean annual temperature: 73.9 °F
ZIP codes (9): 33756 · 33760 · 33762 · 33764 · 33770 · 33771 · 33773 · 33774 · 33778