Frost Line Depth in Knox County, ME: Set Locally (Bangor: 60 in)

No official local value

No official frost line depth is published for Knox County.

No verified code nearby. The only verified Maine code we read, Bangor’s, uses 60 in.

Source and how we checked

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

Climate: 124 nights a year at or below 32 °F (NOAA 1991–2020, Tenants Harbor, 9.5 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

60 inBangor, the only verified Maine code
124nights a year at or below 32 °F
83%of nearby soil rated “moderate” for frost action (USDA)

Does Knox County have an official frost line depth?

No adopted frost line depth found for Knox County in its official documents (checked Oct 2026). No verified code lies near Knox County; the only Maine code we verified, Bangor’s, uses 60 in. Ask the building department for Knox County’s own number before you dig.

What frost line depth does Knox County 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 Knox County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 60 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 Knox County?

Drawn with the deepest Maine official value (60 in). Confirm Knox County’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

House or garage footing in Knox County: dig at least 60 in (152 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Using the nearby official value of 60 in until Knox County confirms its own
Project	Depth	Rule
House or garage footing	60 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	60 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	66 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	60 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 Knox County?

Average lows are at or below freezing from Dec to Mar. 124 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 17.4 °F.

NOAA 1991–2020 climate normals, Tenants Harbor station, 9.5 mi away, elevation 21 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	17.4	19.2	25.4	33.9	42.7	50.2	56.1	56.6	51.5	42.6	33.7	24.4
High	35.2	36.6	42.5	51.4	60.6	68.7	74.2	74	68.2	58.5	49.1	40.6

Knox County has fewer freezing nights than 11 of the 11 other Maine places we track. The Maine median is 162. Coldest: Somerset County; mildest: Knox County.

How likely is the soil in Knox County to heave?

Moderate 83%

USDA rates the sampled soil around Knox County as 5% low, 83% moderate, 11% high for frost action (main soils: Tunbridge, Lyman, Brayton).

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

Knox County at a glance

Frost line depth: No official local value
Population (2023 est.): 40,977
Mean annual temperature: 46.4 °F
ZIP codes (19): 04547 · 04563 · 04574 · 04645 · 04841 · 04843 · 04847 · 04851 · 04853 · 04854 · 04855 · 04856 · 04858 · 04859 · 04860 · 04861 · 04862 · 04863 · 04864