Frost line depth in Otoe County, NE
How deep the ground freezes in Otoe County, NE
33 in. Dig to 33 in, just below the frost. Nearest NOAA station: Syracuse, 3.6 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.