15.04.130 Residential construction.
A. In AE or other A zones areas where the BFE has been determined or can be reasonably obtained, new construction, substantial improvement and/or reconstruction due to substantial damage of any residential structure shall have the lowest floor, including basement, elevated one (1) foot or more above the BFE. All machinery and equipment servicing these structures shall also be elevated one (1) foot or more above BFE.
B. New construction, substantial improvement and/or reconstruction due to substantial damage of any residential structure in an Unnumbered A zone for which a BFE is not available and cannot be reasonably obtained shall be reasonably safe from flooding, but in all cases the lowest floor and machinery and equipment servicing these structures shall be elevated at least two (2) feet above the Highest Adjacent Grade.
C. Fully enclosed areas below the lowest floor that are subject to flooding are prohibited or shall be designed to automatically equalize hydrostatic flood forces on all walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement must either be certified by a registered professional engineer or architect or must meet or exceed the following minimum criteria:
1. A minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding shall be provided. Openings shall be installed in exterior and interior walls.
2. The bottom of all openings shall be no higher than one (1) foot above grade.
3. Openings may be equipped with screens, louvers, or other coverings or devices; provided, that they permit the automatic entry and exit of floodwaters.
4. A garage attached to a residential structure, constructed with the garage floor slab below the BFE, must be designed to allow for the automatic entry and exit of flood waters.
Alternatively, a registered engineer or architect may design and certify engineered openings.
D. Projects developing in the Critical Aquifer Recharge Area are subject to additional requirements under RMC 13.07, Wellhead Protection. (Ord. 3089 § 2 (part), 2022; Ord. 3006 § 2 (part), 2020: Ord. 2737 § 2 (part), 2014: Ord. 2202 § 1 (part), 2004: Ord. 1519 § 1 (part), 1989: Ord. 863 § 8(5), 1979).