Frost Line Depth in Hillsborough County, Florida
- Florida state rule
- Checked Oct 2026
- Sources
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
Hillsborough County does not publish its own value; the state rule applies.
Document: up.codes
Climate: 1 night a year at or below 32 °F (NOAA 1991–2020, Tampa International Airport, 10.9 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Hillsborough County?
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 Hillsborough County?
Florida writes this depth into its statewide residential code, so Hillsborough County’s building department enforces the state’s number rather than setting its own. See how Florida sets frost line depth.
How deep do footings, decks and water lines need to be in Hillsborough County?
House or garage footing in Hillsborough County: dig at least 12 in (30 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| 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 Hillsborough County?
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Hillsborough County never averages a low below freezing. 1 night a year reach 32 °F or colder; Jan is coldest, with an average low of 52.8 °F.
NOAA 1991–2020 climate normals, Tampa International Airport station, 10.9 mi away, elevation 19 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 52.8 | 55.5 | 59.3 | 64.8 | 70.6 | 75.4 | 76.6 | 76.8 | 75.3 | 69.2 | 60.7 | 55.9 |
| High | 71.3 | 74 | 77.8 | 83 | 88.3 | 90.5 | 91 | 91.2 | 90.2 | 85.6 | 78.9 | 73.9 |
Hillsborough County has fewer freezing nights than 53 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 Hillsborough County to heave?
USDA rates the sampled soil around Hillsborough County as 100% none for frost action (main soils: Myakka, Malabar, Pinellas).
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 Hillsborough County?
Hillsborough County at a glance
- Frost line depth
- No Frost Line, 12 in Minimum
- Population (2023 est.)
- 1,535,564
- Mean annual temperature
- 74.5 °F
- ZIP codes (58)
- 33503 · 33510 · 33511 · 33527 · 33530 · 33534 · 33540 · 33547 · 33548 · 33549 · 33550 · 33556 · 33558 · 33559 · 33563 · 33565 · 33566 · 33567 · 33569 · 33570 · 33572 · 33573 · 33578 · 33579 · 33584 · 33592 · 33594 · 33596 · 33598 · 33602 · 33603 · 33604 · 33605 · 33606 · 33607 · 33609 · 33610 · 33611 · 33612 · 33613 · 33614 · 33615 · 33616 · 33617 · 33618 · 33619 · 33620 · 33621 · 33624 · 33625 · 33626 · 33629 · 33634 · 33635 · 33637 · 33647 · 33810 · 33860