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

130, the base flood elevation for Special Flood Hazard Areas identified in the FEMA Flood Insurance Studies for King County (dated August 19, 2020) and Pierce County (dated March 7, 2017) governs all development review in Auburn. The code sets the flood protection elevation, the freeboard standard, at the base flood elevation plus one foot, meaning a structure's lowest floor must sit at least one foot above the mapped base flood elevation to satisfy the city's floodplain rules. The floodway itself is fixed by the boundaries delineated on the Flood Insurance Rate Map.

130(D) directs the floodplain administrator or a designee to obtain and reasonably rely on the best available data from a federal, state, or other qualified source rather than let the project proceed unregulated. 170 requires permit applicants to submit a current elevation certificate showing the proposed elevation of the lowest floor in relation to mean sea level, plus an engineering analysis showing no rise in base flood elevation for any work proposed within a floodway. 190 designates the director of community development as floodplain administrator, with authority to grant or deny floodplain development permits and to delegate administration of the chapter. 180, though the administrator may authorize extensions where delay is beyond the applicant's control. 120(A)(5).