Boulder County, CO Fence Regulations: Height Limits (2026)

Boulder County's fence regulations are administered by Community Planning & Permitting under the Land Use Code (authority CRS §30-28-111). Fences six feet or under in unincorporated Boulder County do not require a building permit, while any fence exceeding six feet must obtain a permit before construction. Sight triangles at road intersections must be preserved at any height — no fence, regardless of dimension, may obstruct the sight triangle, which scales with the posted speed limit of the adjoining roadway. Any proposed fence located within a 100-year floodplain requires a separate Floodplain Development Permit issued by the Boulder County Transportation Department, even when no building permit would otherwise be needed. Agricultural fencing for livestock is generally exempt from permit requirements. Open Space and conservation easement properties carry additional design and material restrictions. Boulder County does not impose city-style 4-foot front yard caps; setback rules apply to structures rather than fences specifically. HOA covenants commonly impose stricter material and height rules in subdivisions like Niwot and Gunbarrel. Boulder County is among the more permissive jurisdictions in Colorado for residential fencing, deferring most aesthetic decisions to property owners.