3 county-level rules, plus city-specific rules for 2 cities in Boulder County, Colorado.
Verified from official government sources
In unincorporated Boulder County, setbacks are set by the Land Use Code Article 4 zoning table. For example, Agricultural (A) requires 35' front, 7' side, 15' rear; Suburban Residential (SR) requires 25' front, 7' side, 15' rear. Setbacks vary by district and road.
Boulder County Land Use Code § 7-1402, Supplementary Requirements for Yards
Cornices, canopies, eaves or similar architectural features may extend two feet into a required yard. Fire escapes may extend six feet into a required rear yard.
In unincorporated Boulder County, residential structures on land platted before August 29, 1994 may reach 35 feet; on other land the maximum is 30 feet, and in no event may any residential structure exceed 35 feet. Some districts allow up to 50 feet for non-residential uses.
Boulder County Land Use Code § 4-101.F.4 (Maximum building height)
On any other land, 30 feet unless, through a subdivided land approval or Site Plan Review approval, a lower or higher height is permitted due to the unique characteristics of the particular site; in no event, however, shall any residential structure exceed 35 feet.
Rather than a flat lot-coverage percentage, unincorporated Boulder County caps Residential Floor Area per parcel, generally the larger of the neighborhood median or a set square-footage bonus over existing floor area, plus minimum lot sizes per zoning district (e.g., 35 acres in Agricultural).
Boulder County Land Use Code § 4-101.E (Maximum Residential Floor Area)
Unless otherwise specified in subsections (ii) through (vi), the maximum Residential Floor Area for a Parcel shall be the larger of either the median Residential Floor Area of the defined Neighborhood or: (A) An additional 1,000 square feet over the existing Residential Floor Area on the Parcel as of May 13, 2025, on a Parcel with 1,500 square feet or less of Residential Floor Area.
2 cities in Boulder County have their own building setbacks & zoning rules. Each link goes to that city's dedicated page with code citations.
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