Floodplain Development Regulations Update - What & Why

Floodplain Development Regulations

What’s Happening Now?

SDCI extended the interim floodplain development regulations a third time for an additional 6 months. The interim regulations are now due to expire February 2023. The proposed permanent floodplain regulations were appealed in July 2021 by the Port of Seattle and since then we have been working with the Port to resolve issues related to the appeal.

The proposed interim floodplain development regulations extension are included on the Project Documents page. 

Project Benefits

Our Floodplain Development Regulations protect people, property, and the environment by regulating the development that occurs in the mapped floodplain and flood prone areas. The new permanent regulations will adopt FEMA's 2019 new Flood Insurance Rate Maps and Flood Insurance Study and will continue to regulate flood prone areas mapped by Seattle Public Utilities. Development regulations vary depending on the specific flood zone designations, characteristics of the property, and the nature of the development including first floor elevation. Below is a list of development regulations:

  1. The elevation that the first floor of a new structure must be built at to keep the first story above anticipated flood levels
  2. Structures must be engineered to withstand wind from anticipated storms
  3. Structures must be engineered to withstand flood waters should anticipated flood levels be exceeded

The End Result

The permanent Floodplain Development Regulations will meet FEMA's 2019 requirements.