Adair County, IA Accessory Structures: Shed & Carport Rules (2026)

Ordinance No. 37 applies, in the words of Section II(A), to "all areas having special flood hazards within the jurisdiction of Adair County," which it defines as the areas designated Zone A on the Flood Insurance Rate Map for Adair County dated April 5, 2017. Outside those mapped areas the ordinance does not reach a shed, and the county's posted ordinances contain no general rule on shed size, setbacks or building permits.

Inside Zone A, Section III(B) requires every new or substantially improved residential structure to have its lowest floor, including basement, elevated a minimum of one foot above the 100-year flood level. Section III(K) carves out detached garages, sheds and similar structures that are incidental to a residential use. They are exempt from the base flood elevation requirements where the listed criteria are satisfied.

The size cap comes first. The structure must be designed to have low flood damage potential, and its size shall not exceed 600 sq. ft. Any portion located less than 1 foot above the BFE must be built of flood-resistant materials. The ordinance defines base flood elevation as the elevation floodwaters would reach at a particular site during a base flood event, meaning the flood with a one percent chance of being equaled or exceeded in any given year.

The use test follows: the structure must be used solely for low flood damage potential purposes such as vehicle parking and limited storage, and it shall not be used for human habitation. It must be placed on the building site so as to offer minimum resistance to the flow of floodwaters, firmly anchored to resist flotation, collapse and lateral movement, and its electrical and heating equipment must be elevated or floodproofed to at least one foot above the base flood elevation. Its walls must include openings that satisfy Section III(D)(1): at least two openings with a total net area of not less than one square inch for every square foot of enclosed area subject to flooding, with the bottom of every opening no higher than one foot above grade, unless an Iowa-registered engineer certifies another design.

Section IV(B)(1) requires a Floodplain Development Permit from the Floodplain Administrator before any floodplain development, a term that covers buildings or other structures. Minor projects valued at less than $500 are excluded from the definition, except for filling, grading and excavating. The posted copy of Ordinance 37 prints a blank adoption date.