Wyoming, MI Environmental Rules: Flood Elevation Requirements (2026)

Sec. 38-6, the chapter's general standards, requires that all new construction, additions and substantial improvements within a flood hazard area have the lowest floor, including any basement, elevated at least one foot above the 100-year floodplain elevation. Sec. 38-11, covering the floodway fringe specifically, restates the freeboard requirement by building type: residential buildings must have the lowest floor, including the basement, elevated to one foot above the regulatory flood level, while nonresidential buildings must either meet that same one-foot elevation or use flood-vented enclosures below the lowest floor designed to equalize hydrostatic pressure, with a minimum of two openings totaling at least one square inch of net area per square foot of enclosed area, positioned no higher than one foot above grade.

New manufactured homes and additions to them must likewise have their lowest floor at least one foot above the 100-year floodplain elevation, and must be anchored with over-the-top and frame ties at each corner (Sec. 38-11(3)-(4)). Mechanical and electrical equipment gets its own one-foot buffer: Sec. 38-6(10) requires new HVAC, plumbing and electrical equipment to be located or elevated at least one foot above the design flood elevation. These freeboard figures are measured against FEMA's Flood Insurance Rate Maps and the Kent County Flood Insurance Study dated February 23, 2023, adopted by reference in Sec. 38-2.