Shoreline, WA Environmental Rules: Flood Elevation Requirements (2026)

SMC § 13.12.105 defines "flood protection elevation (FPE)" as the elevation above the effective flood insurance rate map datum to which new and substantially improved structures must be protected from flood damage, and it fixes that elevation citywide as the base flood elevation (BFE) plus one foot of freeboard. That definition drives the construction standards in SMC § 13.12.505: in AE and A1-30 zones, or other A-zoned areas where the BFE has been determined or can reasonably be obtained, new construction and substantial improvement of any residential structure must have the lowest floor, including any basement, elevated one foot or more above the BFE, and mechanical equipment and utilities must be waterproofed or elevated at least one foot above the BFE as well.

Where no BFE is available for an unnumbered A zone, SMC § 13.12.505(A)(2) falls back to a different rule, requiring the lowest floor to sit at least two feet above the highest adjacent grade. Nonresidential structures get an alternative compliance path under subsection (B): they can meet the same one-foot-above-BFE elevation standard, or ASCE 24 if it demands more, or instead be dry floodproofed watertight to at least one foot above the base flood level, certified by a registered engineer or architect. The floodplain administrator, per SMC § 13.12.800(A)(2), keeps FEMA elevation certificates on file for every new or substantially improved structure in the special flood hazard area, documenting the finished construction elevation actually achieved. Building without meeting the freeboard standard jeopardizes both flood-damage resistance and the structure's National Flood Insurance Program rating.