Frost Line Depth in Nez Perce County, ID: Idaho Codes Range 24

No official local value

No official frost line depth is published for Nez Perce County.

No verified code nearby; verified Idaho codes range 24–36 in.

Source and how we checked

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

Climate: 170 nights a year at or below 32 °F (NOAA 1991–2020, Winchester, 9.3 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

24–36 inrange of verified Idaho codes
170nights a year at or below 32 °F
52%of nearby soil rated “moderate” for frost action (USDA)

Does Nez Perce County have an official frost line depth?

No adopted frost line depth found for Nez Perce County in its official documents (checked Oct 2026). No verified code lies near Nez Perce County; the Idaho codes we verified range from 24 to 36 in. Ask the building department for Nez Perce County’s own number before you dig.

What frost line depth does Nez Perce 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 Nez Perce County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 36 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 Nez Perce County?

Drawn with the deepest Idaho official value (36 in). Confirm Nez Perce County’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

House or garage footing in Nez Perce County: dig at least 36 in (91 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Using the nearby official value of 36 in until Nez Perce County confirms its own
Project	Depth	Rule
House or garage footing	36 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	36 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	42 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	36 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 Nez Perce County?

Average lows are at or below freezing from Nov to Apr. 170 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 22.2 °F.

NOAA 1991–2020 climate normals, Winchester station, 9.3 mi away, elevation 3,972 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	22.8	23.3	27.3	32	38.5	43.4	48.8	48.5	42.3	34.6	27.8	22.2
High	36.6	39.2	45	51.5	60	66.9	78.1	79	69.8	55.6	42.5	34.9

Nez Perce County has more freezing nights than 11 of the 13 other Idaho places we track. The Idaho median is 132. Coldest: Madison County; mildest: Canyon County.

How likely is the soil in Nez Perce County to heave?

Moderate 52%High 48%

USDA rates the sampled soil around Nez Perce County as 52% moderate, 48% high for frost action (main soils: Waha, Linville, Naff).

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

Nez Perce County at a glance

Frost line depth: No official local value
Population (2023 est.): 42,987
Mean annual temperature: 44.6 °F
ZIP codes (10): 83501 · 83524 · 83535 · 83537 · 83540 · 83541 · 83545 · 83548 · 83555 · 83832