Frost Line Depth in Middlesex County, Massachusetts
- Massachusetts state rule
- Checked Oct 2026
- Sources
State-set value
48in
122 cm · 4 ft
48 in (Massachusetts rule)
Set by the state: 780 CMR (10th ed.) Table R301.2(1).
Source and how we checked
Middlesex County does not publish its own value; the state rule applies.
Document: mass.gov
Climate: 147 nights a year at or below 32 °F (NOAA 1991–2020, Maynard 2, 4.4 mi).
Checked Oct 2026. Report a correction
How deep is the frost line in Middlesex County?
Massachusetts sets the frost footing depth for Middlesex County at 48 in (122 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 Middlesex County?
Massachusetts writes this depth into its statewide residential code, so Middlesex County’s building department enforces the state’s number rather than setting its own. See how Massachusetts sets frost line depth.
How deep do footings, decks and water lines need to be in Middlesex County?
House or garage footing in Middlesex County: dig at least 48 in (122 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).
| Project | Depth | Rule |
|---|---|---|
| House or garage footing | 48 in | Below the frost line and at least 12 in deep (IRC R403.1.4) |
| Deck footing (attached) | 48 in | Below the frost line and at least 12 in deep (IRC R507.3) |
| Water service line | 54 in | 6 in below the frost line and at least 12 in deep (IRC P2603.5) |
| Fence post bottom | 48 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 Middlesex County?
- J
- F
- M
- A
- M
- J
- J
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- S
- O
- N
- D
Average lows are at or below freezing from Nov to Mar. 147 nights a year reach 32 °F or colder; Jan is coldest, with an average low of 14.6 °F.
NOAA 1991–2020 climate normals, Maynard 2 station, 4.4 mi away, elevation 205 ft.
Monthly temperatures as a table
| °F | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Low | 14.6 | 15.9 | 23.8 | 33.8 | 45.3 | 54.6 | 60.2 | 58 | 49.4 | 38 | 28.7 | 20.6 |
| High | 37.4 | 40.6 | 48.5 | 61.6 | 73 | 81.1 | 86.9 | 84.9 | 77.5 | 65.5 | 53.6 | 42.8 |
Middlesex County has more freezing nights than 31 of the 38 other Massachusetts places we track. The Massachusetts median is 130. Coldest: Berkshire County; mildest: Malden.
How likely is the soil in Middlesex County to heave?
USDA rates the sampled soil around Middlesex County as 34% low, 54% moderate, 12% high for frost action (main soils: Merrimac, Charlton, Canton).
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 Middlesex County?
Middlesex County at a glance
- Frost line depth
- 48 in (Massachusetts rule)
- Population (2023 est.)
- 1,623,952
- Mean annual temperature
- 49.9 °F
- ZIP codes (83)
- 01431 · 01432 · 01434 · 01450 · 01460 · 01463 · 01464 · 01469 · 01474 · 01701 · 01702 · 01718 · 01719 · 01720 · 01721 · 01730 · 01731 · 01741 · 01742 · 01746 · 01748 · 01749 · 01752 · 01754 · 01760 · 01770 · 01773 · 01775 · 01776 · 01778 · 01801 · 01803 · 01821 · 01824 · 01826 · 01827 · 01850 · 01851 · 01852 · 01854 · 01862 · 01863 · 01864 · 01867 · 01876 · 01879 · 01880 · 01886 · 01887 · 01890 · 02138 · 02139 · 02140 · 02141 · 02142 · 02143 · 02144 · 02145 · 02148 · 02149 · 02155 · 02176 · 02180 · 02420 · 02421 · 02451 · 02452 · 02453 · 02458 · 02459 · 02460 · 02461 · 02462 · 02464 · 02465 · 02466 · 02467 · 02468 · 02472 · 02474 · 02476 · 02478 · 02493