Idaho Falls, ID Fence Regulations: Retaining Walls (2026)

The City of Idaho Falls Comprehensive Zoning ordinance (Title 11) does not separately regulate retaining walls, set a height cap, or assign them setbacks. Retaining walls are instead handled as building/structural work under the city's building regulations. Idaho Falls City Code Section 7-6-1 adopts the International Residential Code for One- and Two-Family Dwellings, 2018 Edition, as the official residential code, and the city's amendments in Section 7-6-2 do not change the code's retaining-wall permit thresholds. Under the standard International Residential and Building Codes the city adopts, a retaining wall is exempt from a building permit only when it is not over four feet (4') in height measured from the bottom of the footing to the top of the wall, unless it supports a surcharge (such as a slope, driveway, or structure above) or impounds Class I, II, or III-A liquids.

Taller walls, or any wall holding back a surcharge, require an engineered design and a building permit. Because soil, slope, and surcharge conditions vary by site, confirm whether your wall needs a permit and stamped plans with the Idaho Falls Building Division before construction.