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

020(R) as a minimum of two feet above the base flood elevation (the 100-year flood level determined by FEMA), except for critical facilities such as schools, hospitals, and emergency response installations, where the minimum rises to three feet above base flood elevation. 130(A)(1) requires that new construction and substantial improvement of any residential structure have the lowest floor, including any basement, elevated to the flood protection elevation. Fully enclosed areas below the lowest floor used solely for parking, access, or storage must either be prohibited or engineered to automatically equalize hydrostatic flood forces, meeting or exceeding a minimum of two openings on at least two separate walls with a total net area of one square inch per square foot of enclosed area, with opening bottoms no higher than one foot above grade, unless certified by a registered engineer or architect.

130(B) must either meet the same elevation standard or be floodproofed to the flood protection elevation so the structure is watertight with substantially impermeable walls. 120(A)(2). The city's economic and community development department administers the chapter, using FEMA's Flood Insurance Study for King County dated August 19, 2020, and the accompanying FIRM as the best available data.