Bonner County, ID Fence Regulations: Retaining Walls (2026)

The engineer rule sits in subchapter 4.7 of Title 12, Standards for Development in the Alpine Village District. Section 12-470 gives its purpose: to provide measures to accommodate snowfall in high elevation communities and to minimize erosion and surface slippage. Section 12-329 establishes the Alpine Village District for recreational development in high elevation communities, in areas designated alpine community by the comprehensive plan. Because the rule is in that subchapter, this page does not state an engineering requirement for retaining walls in other districts.

Section 12-471 A is short and exact: plans for a retaining wall taller than four feet (4') shall bear the stamp of a structural engineer and shall be submitted at the time of building location or building permit. The code defines a retaining wall in section 11-218 as a barrier constructed or placed to resist lateral soil loads or other imposed loads.

The same section stacks related plan requirements. Subsection B requires a snow management plan to the satisfaction of the agency having jurisdiction over the public or private travelways. Subsection C requires a grading, stormwater and erosion control plan containing the minimum requirements of chapter 7, subchapter 7.2 of Title 12, and that plan must also address water resulting from snowmelt on the site and plans to reclaim disturbed ground with native plants having soil holding properties. Section 12-724.1.2 F adds that a grading plan shows the location, elevation, width and configuration of any benches, terraces, retaining walls or other slope treatments.

Short walls are treated differently. Section 11-219 lists retaining walls not over four feet (4') in height measured at grade among the exceptions to the definition of a structure. Those exceptions remain subject to the land use standards in Title 12, but they are not subject to the setback standards specified in title 12 chapter 4. Fences not over eight feet (8') in height measured at grade sit on the same list.