Summary: Seattleā€™s Floodplain Development Ordinance (FDO) Seattle Municipal Code Chapter 25.06 imposes standards and restrictions for construction and development in designated special flood hazard areas in the city. The areas affected by the regulations are located within the designated 100-year floodplain along Thornton, Pipers and Longfellow Creeks, in the South Park area along the Duwamish Waterway, and along the coastline of Puget Sound. These special flood hazard areas are identified by the letters A or V on the Flood Insurance Rate Map (FIRM). The flood regulations create permit requirements for new construction that applicants having property located in the designated areas should be familiar with.

Date Revised: 04/05/2022

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