Frost Line Depth in Mercer County, PA: Pennsylvania Codes Range 30

No official local value

No official frost line depth is published for Mercer County.

No verified code nearby; verified Pennsylvania codes range 30–36 in.

Source and how we checked

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

Climate: 158 nights a year at or below 32 °F (NOAA 1991–2020, Mercer, 5.3 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

30–36 inrange of verified Pennsylvania codes
158nights a year at or below 32 °F
86%of nearby soil rated “high” for frost action (USDA)

Does Mercer County have an official frost line depth?

No adopted frost line depth found for Mercer County in its official documents (checked Oct 2026). No verified code lies near Mercer County; the Pennsylvania codes we verified range from 30 to 36 in. Ask the building department for Mercer County’s own number before you dig.

What frost line depth does Mercer County use for footings under Table R301.2(1)?

Call 811 (PA One Call) at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Mercer 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 Mercer County?

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

House or garage footing Deck footing Water service line Fence post

House or garage footing in Mercer 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 Mercer 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 Mercer County?

Average lows are at or below freezing from Nov to Mar. 158 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 16.1 °F.

NOAA 1991–2020 climate normals, Mercer station, 5.3 mi away, elevation 1,220 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	16.1	17.3	24.7	33.9	43.9	53.2	56.4	55.9	48.6	38.2	29.2	21.3
High	34.9	38.5	48.4	61.7	71.2	78.7	81.9	81.5	75.2	63.3	50.3	39.9

Mercer County has more freezing nights than 4 of the 4 other Pennsylvania places we track. The Pennsylvania median is 134. Coldest: Mercer County; mildest: Reading.

How likely is the soil in Mercer County to heave?

Moderate 14%High 86%

USDA rates the sampled soil around Mercer County as 14% moderate, 86% high for frost action (main soils: Ravenna, Canfield, Frenchtown).

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

Mercer County at a glance

Frost line depth: No official local value
Population (2023 est.): 108,503
Mean annual temperature: 48.5 °F
ZIP codes (28): 16057 · 16110 · 16113 · 16114 · 16121 · 16124 · 16125 · 16127 · 16130 · 16133 · 16134 · 16137 · 16142 · 16143 · 16145 · 16146 · 16148 · 16150 · 16151 · 16153 · 16154 · 16156 · 16159 · 16161 · 16311 · 16314 · 16342 · 16362