Floodplain Development Regulations Update - What & Why

What’s Happening Now?

FEMA adopted new Flood Insurance Rate Maps and a Flood Insurance Study for all jurisdictions in King County, including Seattle, which requires us to adopt new Floodplain Development Regulations. To meet this requirement we adopted interim Floodplain Development Regulations that took effect on August 23, 2020 and we are currently working on permanent Floodplain Development Regulations to meet FEMA's requirements.

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. Structures must be engineered to withstand wind from anticipated storms
  2. Structures must be engineered to withstand flood waters should anticipated flood levels be exceeded
  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.