Fort Collins, CO Environmental Rules: Flood Elevation Requirements (2026)

Section 10-37 of the Fort Collins Municipal Code sets the City's freeboard standard for every structure built, added to, substantially improved, or redeveloped inside a designated flood hazard area under Chapter 10, Article II. The base flood elevation for a parcel is the higher of the elevation shown on the FEMA Flood Insurance Rate Map or the elevation from the City's own floodplain delineation adopted under Section 10-19(b); where no base flood elevation is mapped for an AO zone, the code defaults to 24 inches above the highest adjacent grade.

Elevation is then layered on top of that number. Ductwork, HVAC systems, the hot water heater, electrical equipment, and the lowest floor must be raised to or above the regulatory flood protection elevation for any new construction, addition, substantial improvement, repair of substantial damage, or redevelopment. The amount of freeboard depends on the floodplain and the type of work: 24 inches above base flood elevation anywhere in the Poudre River floodplain; 18 inches above base flood elevation for new construction and full redevelopments in FEMA basin and City basin floodplains (Dry Creek, Spring Creek, Boxelder Creek, Cooper Slough, Old Town, West Vine, Canal Importation, Fossil Creek, Mail Creek, McClellands Creek and Foothills); and 12 inches above base flood elevation for additions, substantial improvements, and accessory structures in those same basin floodplains.

Where the lowest floor is measured depends on the foundation type: at the top of the slab for slab-on-grade, the top of the basement slab for a basement, or interior grade for a noncompliant crawl space or enclosure. Nonresidential structures, accessory structures and attached garages may substitute floodproofing under Section 10-38 if flood depth around the structure does not exceed 3 feet, and qualifying crawl spaces and enclosures may use the venting standards of Section 10-39 instead of full elevation. Before the City's Utilities Executive Director will release a certificate of occupancy, the owner must submit a FEMA elevation certificate signed by a registered professional land surveyor documenting the as-built elevation.