Pasco, WA Frost Line Depth: 24 in

Verified

24in

61 cm · 2 ft

Set in the building code Pasco has adopted.

Source and how we checked

Document: pasco-wa.gov

Climate: 112 nights a year at or below 32 °F (NOAA 1991–2020, Pasco Tri Cities Airport, 0.2 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

1 of 1nearby verified codes use the same depth
112nights a year at or below 32 °F
86%of nearby soil rated “low” for frost action (USDA)

How deep is the frost line in Pasco?

Pasco's building authority sets the frost line depth at 24 in (61 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 Pasco?

Washington leaves the frost line depth to each city or county, and Pasco fills it in when it adopts the residential code. The value above comes from Pasco’s own document on pasco-wa.gov. Franklin County uses the same 24 in, so the depth does not change at the city limits. See how Washington sets frost line depth.

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

House or garage footing Deck footing Water service line Fence post

House or garage footing in Pasco: dig at least 24 in (61 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Minimum depths in Pasco with a 24 in frost line
Project	Depth	Rule
House or garage footing	24 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	24 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	30 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	24 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 Pasco?

Average lows are at or below freezing from Nov to Feb. 112 nights a year reach 32 °F or colder; Dec is coldest, with an average low of 27.3 °F.

NOAA 1991–2020 climate normals, Pasco Tri Cities Airport station, 0.2 mi away, elevation 407 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	27.8	28.2	33.1	38.4	46.3	52.6	56.9	55.7	47.6	38.4	31.9	27.3
High	41.4	48.6	58.6	67	76.5	83.1	92.5	90.7	80.9	65.8	49.9	41

Pasco has more freezing nights than 38 of the 47 other Washington places we track. The Washington median is 54. Coldest: Chelan County; mildest: Lakewood.

What frost line depth do towns near Pasco use?

One official code near Pasco is verified.

Official frost line depths near Pasco
Place	Verified frost line	Distance
Franklin County	24 in	21 mi away

How likely is the soil in Pasco to heave?

Low 86%High 14%

USDA rates the sampled soil around Pasco as 86% low, 14% high for frost action (main soils: Quincy, Winchester, Royal).

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 Pasco?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Pasco building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 24 in unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

Pasco at a glance

Frost line depth: 24 in
County: Franklin County
Population (2023 est.): 80,038
Mean annual temperature: 53.3 °F
ZIP codes (1): 99301