Waterloo, IA Environmental Rules: Flood Elevation Requirements (2026)

Waterloo City Code § 11-5-4, the drainage and storm sewers chapter of the subdivision regulations (Title 11), governs how flood-prone land can be platted inside the city limits. Under subsection B.5, "Areas Of Poor Drainage," the City Council may approve a subdivision plat covering land subject to flooding only if the applicant raises the site so that the "lowest water entry level" of every structure sits at least twelve inches above the 100-year flood elevation, extending that fill at least ten feet in every direction around the building.

The City Engineer determines the exact elevation and the boundaries of the required fill area, and the plat must also lay out an overflow zone along any stream or watercourse bank wide enough to carry high water; no fill, structure, or obstruction may be placed inside that overflow zone. Subsection B.6 lets the Council go further and bar subdivision entirely within a "flood fringe area" when it finds the restriction necessary for health, safety, water conservation, drainage or sanitary facilities. Subsection B.7 draws the hardest line: the Council must prohibit subdivision of any land inside the city designated floodway, whether the proposed use is residential, commercial, or industrial.

This provision sits entirely inside the platting process administered by the Planning, Programming and Zoning Commission and the City Engineer; it is separate from Waterloo's standalone zoning ordinance, which is not part of this code.