Lane County, OR Frost Line Depth: 12 in

Verified

12in

30 cm · 1 ft

Set in the building code Lane County has adopted.

Source and how we checked

Document: lanecountyor.gov

Climate: 27 nights a year at or below 32 °F (NOAA 1991–2020, Lookout Pt Dam, 6.9 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

2 of 2nearby verified codes use the same depth
27nights a year at or below 32 °F
57%of nearby soil rated “low” for frost action (USDA)

How deep is the frost line in Lane County?

Lane County's building authority sets the frost line depth at 12 in (30 cm). Footings, piers and other permanent supports must reach at least this depth (IRC R403.1.4.1).

Who sets the frost line depth in Lane County?

Oregon sets frost line depth in its state code, and Lane County’s own document lists the value above (lanecountyor.gov). See how Oregon sets frost line depth.

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

House or garage footing Deck footing Water service line Fence post

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

Minimum depths in Lane County 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 Lane County?

Lane County never averages a low below freezing. 27 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 36.9 °F.

NOAA 1991–2020 climate normals, Lookout Pt Dam station, 6.9 mi away, elevation 712 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	37.1	37.8	39.8	42.5	46.7	50.7	54.7	54.5	52.2	47.2	41.5	36.9
High	46.9	50.3	54.2	58.5	64.9	70.8	79.8	80	74.2	62.8	52	46

Lane County has fewer freezing nights than 21 of the 22 other Oregon places we track. The Oregon median is 54. Coldest: Deschutes County; mildest: Lincoln County.

What frost line depth do towns near Lane County use?

2 official codes near Lane County are verified; each links to its document.

Official frost line depths near Lane County
Place	Verified frost line	Distance
Corvallis	12 in	48 mi away
Marion County	12 in	69 mi away

How likely is the soil in Lane County to heave?

None 43%Low 57%

USDA rates the sampled soil around Lane County as 43% none, 57% low for frost action (main soils: Courtney, Dixonville, Chehulpum).

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 Lane County?

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

Lane County at a glance

Frost line depth: 12 in
Population (2023 est.): 381,181
Mean annual temperature: 53.4 °F
ZIP codes (39): 97324 · 97390 · 97401 · 97402 · 97403 · 97404 · 97405 · 97408 · 97412 · 97413 · 97419 · 97424 · 97426 · 97430 · 97431 · 97434 · 97437 · 97438 · 97439 · 97446 · 97448 · 97451 · 97452 · 97453 · 97454 · 97455 · 97456 · 97461 · 97463 · 97477 · 97478 · 97480 · 97487 · 97488 · 97489 · 97490 · 97492 · 97493 · 97498