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's May 2025 Land Use Code controls building intensity through maximum Residential Floor Area rather than a simple coverage ratio. Unless otherwise specified, the maximum Residential Floor Area for a parcel is the larger of the median Residential Floor Area of the defined Neighborhood or a bonus over existing floor area, for example an additional 1,000 square feet on a parcel with 1,500 square feet or less. The Assessor's records and Community Planning & Permitting determine the neighborhood median. Minimum lot sizes also apply by district (35 acres unsubdivided in most districts; 7,500 sq. ft. in Suburban/Multifamily with water and sewer). The Director may limit floor area further as a mitigation measure.
Exceeding the maximum Residential Floor Area without approval can result in permit denial or a Site Plan Review requirement; unpermitted floor area is a code violation subject to enforcement.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
Boulder County, CO
Boulder County has no separate 'hoarding' ordinance, but Ordinance 2022-8 makes it unlawful to fail to provide any livestock or domestic animal with minimum ...
Boulder County, CO
Boulder County residents may not intentionally feed big game or bears. Colorado Parks and Wildlife regulation and C.R.S. 33-6-131 make it illegal to intentio...
Boulder County, CO
Backyard composting is allowed and strongly encouraged in Boulder County. The county's Zero Waste program provides compost collection, but home compost piles...
Boulder County, CO
Boulder County sets no countywide ban on residential artificial turf. Colorado SB23-178 prevents HOAs from prohibiting nonvegetative turf grass, though droug...
Boulder County, CO
Boulder County encourages native and water-wise landscaping and imposes no lawn requirement on rural land. Colorado law (SB23-178) bars HOAs from banning xer...
Boulder County, CO
Under Colorado HB16-1005, Boulder County residents may collect rooftop rainwater in up to two rain barrels totaling no more than 110 gallons, for outdoor use...
See how Boulder County's lot coverage limits rules stack up against other locations.
Help us keep this page accurate. If you notice an error or outdated information, let us know.