Frost line depth in King County, WA

How deep the ground freezes in King County, WA

5 in. Dig to 12 in, the 12 in code minimum. Nearest NOAA station: Snoqualmie Falls, 3.5 mi.

Your building department sets the legal frost line depth (IRC Table R301.2(1)); footings must go below it (R403.1.4.1). Call them before you dig.

12 in minimum · Snow