Kansas leaves residential building codes to cities and counties, which adopt a model code by reference if they adopt one at all, so there is no state frost depth number and the figure that governs your footing comes from your local building department.
Kansas leaves the frost line depth to the local building department, which is where the number for an address comes from.
Any city is hereby authorized and empowered to incorporate in an ordinance by reference, in the manner hereinafter provided, any standard or model code or ordinance, regulation having the effect of law of a state officer, board or other agency, or statute, or portions thereof on any subject on which a city may legislate, which standard or model code or ordinance or state regulation is available in book or pamphlet formK.S.A. 12-3009, Subjects which may be incorporated in ordinance by reference, Kansas Office of Revisor of Statutes, read September 22, 2026. Read it at the source
That makes the building department issuing the permit the office with the number, and it is a short call: the counter gives the depth for the address, and the same call settles whether a deck footing or a slab edge needs a footing inspection before the concrete goes in. What Kansas does publish is below, and it is worth having in hand first.
The air freezing index is the quantity the frost provisions of the model codes are written on: add up how far each day’s mean temperature fell below freezing over a winter, in degree days, and take the deepest run the winter managed. It measures how much cold the ground had to absorb, which is why it is the honest way to set one place beside another. Goodland is the coldest of the 3 cities on the record in Kansas.
357degree days
average freezing index a winter
Goodland Renner Field
| City | State | Freezing index | Once a century | Nights below freezing |
|---|---|---|---|---|
| Goodland | Kansas | 357 | 973 | 158 |
| Topeka | Kansas | 329 | 959 | 118 |
| Wichita | Kansas | 215 | 680 | 107 |
Computed from NOAA National Centers for Environmental Information, Global Historical Climatology Network daily temperature records for each station, from 1951 onward. These are measurements of winter, not depths.
Only a handful of states answer with one number for the whole state, and they are the only codes that can be set beside each other directly. Ranked by the freezing index at their own reference cities, with Kansas marked at 300 degree days for comparison against what those codes settled on:
Left to right, the mildest winters to the hardest. The figure on the right is what that state wrote into its code.
The nearest by winter are Massachusetts at 4 feet, Connecticut at 42 inches and North Carolina at 12 inches. That is a reading of other states’ codes rather than a depth for an address in Kansas: soil, drainage, snow cover and local amendments all move the figure, and the building department issuing the permit is the office whose number binds.
Kansas code read September 22, 2026 from K.S.A. 12-3009, Subjects which may be incorporated in ordinance by reference, Kansas Office of Revisor of Statutes. Codes are amended and a local amendment can be deeper than the state figure, so the building department issuing the permit has the number that binds. Every state is on the frost line depth hub.