Centennial, CO Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Minimum freeboard
- 2 feet above base flood elevation
- Applies to
- substantial improvements
- Certification
- PE, architect, or land surveyor
- Critical facilities
- also 2 feet above BFE
Summary
Substantially improved structures in a Centennial floodplain must elevate their lowest floor at least two feet above the 100-year base flood elevation, certified by a licensed professional.
E.Freeboard. A minimum clearance, or freeboard shall, be provided between the floodplain or adjacent to the floodplain or shallow flooding area and structures and other applicable facilities which may be impacted by the base flood. Freeboard is required to allow for uncertainty in the floodplain modeling, changes to drainageway (i.e., increased invert due to sedimentation), upstream development and to provide an additional factor of safety (buffer) for structures and facilities which would experience damages or hazards during inundation.1.The City requires a minimum of two (2) feet of freeboard between the 100-year water surface elevation and the lowest floor elevation of all substantially improved structures in the floodplain or adjacent properties to the floodplain.
Full Breakdown
LDC § 12-7-304(E) requires two feet of 'freeboard', clearance above the base flood elevation, for any substantially improved structure in or adjacent to a floodplain, covering both residential and nonresidential buildings. Residential substantial improvements must have their lowest floor elevated to at least two feet above the 100-year base flood elevation, or two feet above grade in shallow AO/AH flood zones, certified on an Elevation Certificate by a Colorado-registered engineer, architect, or land surveyor. Nonresidential buildings can meet the same freeboard or instead flood-proof to that height with watertight, structurally reinforced walls, certified by a licensed professional.
Violations & Fines
Building below the required freeboard without a floodplain permit violates the LDC; the Floodplain Administrator can withhold permits, and municipal court may fine up to $2,650 per day (§§ 12-15-302, 1-4-10).
Frequently Asked Questions
How high above flood level must I build in a Centennial floodplain?
Who certifies my home meets the freeboard requirement?
Sources & Official References
Other rules in Centennial
Compare Centennial to another location·View the Colorado environmental rules overview
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Flood Elevation Requirements in Nearby Cities
How other cities in Arapahoe County handle flood elevation requirements.