Olathe, KS Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard required
- 2 feet above BFE
- Applies to
- new/substantially improved homes
- Certification
- licensed surveyor or engineer
- Enforced by
- Floodplain Administrator
Summary
Olathe requires new or substantially improved residential structures in the 100-year floodplain to elevate their lowest floor at least 2 feet above base flood elevation, certified by a licensed surveyor or engineer.
New construction or substantial-improvement of any residential structures on any lot or lots adjacent to or part of the 100-year floodplain, including manufactured homes, shall have the lowest floor, including basements as well as utilities, mechanical and HVAC equipment servicing the building, elevated a minimum of two (2) feet above base flood elevation. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer.
2. Non Residential Construction New construction or substantial-improvement of any commercial, industrial, or other non-residential structures, including manufactured homes, shall have the lowest floor, including basements as well as utilities, mechanical and HVAC equipment servicing the building, elevated a minimum of two (2) feet above the base flood elevation or, together with attendant utility and sanitary facilities, be floodproofed to a minimum of two (2) feet above the base flood elevation. A registered professional engineer or architect shall certify that the standards of this subsection are satisfied. The elevation of the lowest floor shall be certified by a licensed land surveyor or professional engineer. The certification shall be provided to the floodplain administrator as set forth in subsection D.3.g, h, and i.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 26-39, passed July 21, 2026).
Full Breakdown
Olathe's floodplain chapter sets a local freeboard standard beyond the bare FEMA minimum: new construction or substantial improvement of a residential structure, including manufactured homes, anywhere in the 100-year floodplain must have its lowest floor, basement, and all mechanical, utility, and HVAC equipment elevated at least 2 feet above base flood elevation. Non-residential buildings get the same 2-foot freeboard or may floodproof to that height instead. A licensed land surveyor or professional engineer must certify the finished elevation, and that certification goes to the Floodplain Administrator before a permit is finalized.
Violations & Fines
Building below the 2-foot freeboard without certification blocks issuance of a floodplain development permit and can jeopardize NFIP flood insurance eligibility; the City may also pursue civil remedies under UDO Chapter 18.70.
Frequently Asked Questions
How much above base flood elevation must a new house be built in Olathe?
Who certifies compliance with Olathe's freeboard rule?
Sources & Official References
Other rules in Olathe
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Flood Elevation Requirements in Nearby Cities
How other cities in Johnson County handle flood elevation requirements.