Lynnwood, WA Environmental Rules: Flood Zones (2026)

Chapter 16.46 applies citywide to every area of special flood hazard identified in "The Flood Insurance Study for Snohomish County, Washington and Incorporated Areas," dated June 19, 2020, and its accompanying flood insurance rate maps, both adopted by reference under LMC 16.46.030(B). No structure or land may be constructed, extended, converted, or altered in a flood hazard area without full compliance with the chapter, and a development permit must be obtained before construction or development begins, covering structures, manufactured homes, fill, and other regulated activities (LMC 16.46.040(A)(1)).

The public works director administers the program, reviewing permits to confirm the site is reasonably safe from flooding and that any floodway encroachment meets LMC 16.46.050(C)(1). New residential construction and substantial improvements must have the lowest floor, including any basement, elevated at least one foot above base flood elevation, and fully enclosed areas below that floor must either be prohibited or fitted with flood-venting openings totaling at least one square inch per square foot of enclosed area, with the lowest opening no more than one foot above grade (LMC 16.46.050(A)(1), (B)(1)).

A three-member appeal board, appointed by the mayor, hears variance requests and appeals from the director's decisions, with further appeal to Snohomish County superior court. Variances are reserved for narrow circumstances, generally lots of a half-acre or less surrounded by existing below-base-flood-level structures, and any variance granted must come with written notice that flood insurance premiums can run as high as $25.00 per $100.00 of coverage.