Des Moines, IA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard required
- 3 feet above base flood elevation
- Applies to
- new or substantially improved structures
- Permit needed
- certificate of compliance (§ 50-35)
- Administered by
- city engineer (§ 50-32.05)
- Nonresidential option
- floodproofing instead of elevating
Summary
New construction and substantial improvements in Des Moines floodplains must elevate the lowest floor at least three feet above the 100-year base flood elevation, the city's required freeboard margin.
All residential buildings and factory-built homes (whether or not placed in existing factory-built home parks or subdivisions) for which the start of construction commenced on or after February 4, 1981, or to which substantial improvements have been made on or after February 4, 1981, shall have the lowest floor, including basement, elevated equal to or above the minimum flood protection elevation.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 38 Update 1).
Full Breakdown
Des Moines Municipal Code § 50-34(2) requires residential structures and factory-built homes built, or substantially improved, in a mapped floodplain to have the lowest floor, including any basement, elevated to or above the 'minimum flood protection elevation.' Section 50-26 defines that elevation as three feet of freeboard above the FEMA 100-year base flood elevation, except in AO zones, which use the rate-map depth figure plus one foot. Nonresidential buildings under § 50-34(3) may floodproof instead of elevate, certified by a state-licensed engineer. The city engineer administers compliance through the § 50-35 certificate-of-compliance process before any building, grading, or subdivision permit issues.
Violations & Fines
Building without a certificate of compliance is a misdemeanor under § 1-15 or a municipal infraction civil penalty per § 50-36; the city engineer can also deny or revoke building, grading, subdivision and zoning-compliance permits until standards are met.
Frequently Asked Questions
How much freeboard does Des Moines require above the 100-year flood elevation?
Can a commercial building in a Des Moines floodplain skip elevating and floodproof instead?
Sources & Official References
Other rules in Des Moines
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