There are 31 miles of mapped streams within the corporate boundaries of Mason City. In order to maximize the potential of our waterfront while at the same time enhancing public safety and property values, the City has adopted flood plain regulations that govern development within the City's mapped flood plains. Mason City is a delegated community. This means the City is responsible for nearly all flood plain administration within the city limits. A local flood plain development permit is required for all development in the regulated floodplain. Floodplain regulations are found in the City's Zoning Ordinance (Title 12 of the Municipal Code.) FEMA has issued new maps for all of Cerro Gordo County, including Mason City. These maps will become effective on June 5, 2020. The new maps and the flood insurance study can be viewed online at the FEMA Map Service Center.
Residents and developers in Mason City should note that the City of Mason City regulates most Shaded Zone X flood plain areas in the same way we regulate AE flood zones. If your property is in a Shaded Zone X area, please contact the Flood Plain Administrator at 641-421-3626 to determine if development is subject to the City's Flood Plain Management Ordinance.