Littleton, CO Environmental Rules: Flood Elevation Requirements (2026)

E, General Construction Standards, requires all new construction and substantial improvements in or adjacent to the floodplain to be anchored against flotation and lateral movement, built with flood-resistant methods and materials, and to have electrical, heating, plumbing and HVAC equipment elevated at least one foot above the base flood elevation and protected from water intrusion. 4, Freeboard, sets the core rule: a minimum vertical clearance of one foot between the floodplain elevation and the lowest floor, including basement, of every new or substantially improved structure, added to account for uncertainty in floodplain modeling, drainageway changes, and to provide a margin of safety.

Subsection G, Residential Construction Standards, applies the same one-foot floor elevation to new residential construction, substantial improvement, and rebuilding after substantial damage, and in FEMA Zones A, AO, AH or other shallow-flooding areas requires the lowest floor to sit one foot above either the highest adjacent grade, the base flood elevation, or the FIRM's mapped depth number, whichever is greater, rising to three feet of freeboard if no depth number is mapped. Manufactured homes and their supporting utilities must likewise be elevated at least one foot above the base flood elevation and anchored against flotation, collapse and lateral movement, on top of separate state and local wind-anchoring rules. 8 authorizes this freeboard as one of the safeguards the city may impose as a condition of floodplain development approval.