Porter County, IN Frost Line Depth: 36 in

Verified

36in

91 cm · 3 ft

Set in the building code Porter County has adopted.

Source and how we checked

Document: portercountyin.gov

Climate: 124 nights a year at or below 32 °F (NOAA 1991–2020, Valparaiso Wtr Wks, 1.7 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

124nights a year at or below 32 °F
73%of nearby soil rated “high” for frost action (USDA)

How deep is the frost line in Porter County?

"{confirmed quote}". Footings, piers and other permanent supports must reach at least this depth (IRC R403.1.4.1).

Who sets the frost line depth in Porter County?

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

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

House or garage footing Deck footing Water service line Fence post

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

Minimum depths in Porter County with a 36 in frost line
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 Porter 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 17.6 °F.

NOAA 1991–2020 climate normals, Valparaiso Wtr Wks station, 1.7 mi away, elevation 800 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	17.6	21.4	29.1	39.1	49.3	58.5	63.1	61.7	54.3	44	33.5	23.7
High	32.1	36.4	47.6	60.7	71.2	79.7	82.9	81	75.2	63.6	49.1	36.6

Porter County has more freezing nights than 35 of the 55 other Indiana places we track. The Indiana median is 120. Coldest: LaGrange County; mildest: Evansville.

How likely is the soil in Porter County to heave?

Moderate 27%High 73%

USDA rates the sampled soil around Porter County as 27% moderate, 73% high for frost action (main soils: Blount, Sebewa, Washtenaw).

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 Porter County?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Porter County building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 36 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Porter County at a glance

Frost line depth: 36 in
Population (2023 est.): 175,335
Mean annual temperature: 50.5 °F
ZIP codes (16): 46301 · 46302 · 46304 · 46307 · 46341 · 46342 · 46347 · 46348 · 46360 · 46368 · 46383 · 46385 · 46390 · 46391 · 46393 · 46403