Frost Lines By State 2020

The frost line, also referred to as the frost depth, is the depth at which the groundwater in soil is expected to freeze. Frost lines depend on the climatic conditions of an area, including the heat transfer properties of materials in the ground (such as soil) and nearby heat sources.

Frost lines vary by latitude and are deeper closer to the poles. In the contiguous United States, according to the Federal Highway Administration, the maximum frost depth ranges between zero to eight feet.

Frost lines can be important for building construction and are taken into consideration when laying a foundation. When water transitions from liquid to solid, it expands 9% in volume. Frost heaving, which is the upward swelling of soil during freezing conditions, can move the foundations of buildings, severely damaging them. For this reason, building codes will consider frost lines and build the foundations below the line. Additionally, water and sewer pipes need to be placed below the frost lines as well.

Frost Lines by State

Alabama

  • State average frost depth: 6 inches

Alaska

  • State average frost depth: 100 inches

Arizona

  • State average frost depth: 10 inches

Arkansas

  • State average frost depth: 14 inches

California

  • State average frost depth: 5 inches

Colorado

  • State average frost depth: 44 inches

Connecticut

  • State average frost depth: 36 inches

Delaware

  • State average frost depth: 32 inches

District of Columbia

  • State average frost line: 30 inches

Florida

  • State average frost line: zero inches

Georgia

  • State average frost depth: 5 inches

Hawaii

  • State average frost depth: zero inches

Idaho

  • State average frost depth: 31 inches

Illinois

  • State average frost depth: 36 inches

Indiana

  • State average frost depth: 36 inches

Iowa

  • State average frost depth: 58 inches

Kansas

  • State average frost depth: 32 inches

Kentucky

  • State average frost depth: 15 inches

Louisiana

  • State average frost depth: 4 inches

Maine

  • State average frost depth: 74 inches

Maryland

  • State average frost depth: 30 inches

Massachusetts

  • State average frost depth: between 30 and 35 inches

Michigan

  • State average frost depth: 42 inches

Minnesota

  • State average frost depth: 80 inches

Mississippi

  • State average frost depth: 8 inches

Missouri

  • State average frost depth: between 30 and 36 inches

Montana

  • State average frost depth: 61 inches

Nebraska

  • State average frost depth: 48 inches

Nevada

  • State average frost depth: 23 inches

New Hampshire

  • State average frost depth: 60 inches

New Jersey

  • State average frost depth: 36 inches

New Mexico

  • State average frost depth: 18 inches

New York

  • State average frost depth: 50 inches

North Carolina

  • State average frost depth: 10 inches

North Dakota

  • State average frost depth: 75 inches

Ohio

  • State average frost depth: 32 inches

Oklahoma

  • State average frost depth: 20 inches

Oregon

  • State average frost depth: 18 inches

Pennsylvania

  • State average frost depth: 44 inches

Rhode Island

  • State average frost depth: 38 inches

South Carolina

  • State average frost depth: 4 inches

South Dakota

  • State average frost depth: 64 inches

Tennessee

  • State average frost depth: 12 inches

Texas

  • State average frost depth: 10 inches

Utah

  • State average frost depth: 30 inches

Vermont

  • State average frost depth: 60 inches

Virginia

  • State average frost depth: 18 inches

Washington

  • State average frost depth: 24 inches

Wisconsin

  • State average frost depth: 65 inches

Wyoming

  • State average frost depth: 56 inches

Frost Lines By State 2020

Source:
State 2020 Pop.
Alabama4,908,620
Alaska734,002
Arizona7,378,490
Arkansas3,039,000
California39,937,500
Colorado5,845,530
Connecticut3,563,080
Delaware982,895
District of Columbia720,687
Florida21,993,000
Georgia10,736,100
Hawaii1,412,690
Idaho1,826,160
Illinois12,659,700
Indiana6,745,350
Iowa3,179,850
Kansas2,910,360
Kentucky4,499,690
Louisiana4,645,180
Maine1,345,790
Maryland6,083,120
Massachusetts6,976,600
Michigan10,045,000
Minnesota5,700,670
Mississippi2,989,260
Missouri6,169,270
Montana1,086,760
Nebraska1,952,570
Nevada3,139,660
New Hampshire1,371,250
New Jersey8,936,570
New Mexico2,096,640
New York19,440,500
North Carolina10,611,900
North Dakota761,723
Ohio11,747,700
Oklahoma3,954,820
Oregon4,301,090
Pennsylvania12,820,900
Rhode Island1,056,160
South Carolina5,210,100
South Dakota903,027
Tennessee6,897,580
Texas29,472,300
Utah3,282,120
Vermont628,061
Virginia8,626,210
Washington7,797,100
West Virginia1,778,070
Wisconsin5,851,750
Wyoming567,025