Shoreline, WA Environmental Rules: Flood Zones (2026)

Chapter 13.12 SMC exists, per SMC § 13.12.100, to protect life and property from flooding, keep Shoreline eligible for the National Flood Insurance Program, and preserve natural floodplain and habitat functions, and it applies to the special flood hazard area (SFHA) shown on FEMA's flood insurance rate maps. SMC § 13.12.500(A) sets the baseline rule: any new structure, substantially improved building, repair to a substantially damaged building, manufactured home placement, or recreational vehicle sited for more than 180 days within the SFHA must be protected from flood damage below the flood protection elevation.

Subsection (B)'s general standards require the structure to align with flood flow direction where practicable, be anchored against flotation and lateral movement from hydrodynamic and hydrostatic loads, use flood-damage-resistant materials below the flood protection elevation, and elevate electrical, heating, plumbing, and HVAC equipment above that elevation. Fully enclosed areas below the lowest floor are barred unless they include flood-venting openings meeting specific size and placement criteria. SMC § 13.12.400 layers on subdivision and site-design rules, including a ban on siting new subdivisions that lack a buildable area outside the floodplain and a requirement that new impervious surface covering more than 10 percent of a lot's floodplain portion show no net increase in stormwater runoff.

New critical facilities, such as schools or fire stations, generally must locate outside the SFHA, and hazardous materials beyond normal household quantities are prohibited from the regulatory floodplain under SMC § 13.12.400(C). The floodplain administrator, the Planning and Community Development director, reviews permits under SMC § 13.12.700 and can grant a variance only on a showing of exceptional hardship under SMC § 13.12.800(C).