Flood Hazard


Snohomish County is one of nearly 20,000 communities across the United States that participate in the National Flood Insurance Program. This program requires the county to adopt and enforce floodplain management ordinances and development regulations to reduce future flood damage. In return, the National Flood Insurance Program makes federally-supported flood insurance available to homeowners, renters, and business owners in Snohomish County’s flood hazard areas


The basic premise of this program is that it is safer and less costly to minimize flood damage through appropriate development codes in flood hazard areas, and to insure against future flood damage instead of relying on more costly disaster-relief assistance after a flood event.


What are Flood Hazard Areas?

Areas that flood are given different designations such as floodway fringe, density fringe and hydraulic floodway. These areas are mapped and have specific provisions and requirements for development. The designations are based on the Digital Federal Insurance Rate Maps (DFIRM). These maps are based on detailed inter-agency collaboration and form the standards for participation in the National Flood Insurance Program.

Information about 2020 code update related to Special Flood Hazard Areas:  

For more information about flood hazard areas or development in these areas please see the information packet and bulletin links below.

Is my project in a flood hazard area?

FEMA Flood Map Service Center

PDS Map Portal (click to view instructions for navigating to 2019 Flood Maps layer)

Flood Hazard Permit

Projects proposed within a designated flood hazard area will require a Flood Hazard Permit and accompanying elevation certificate. A separate permit and elevation certificate is required for each individual structure on a parcel.


Fill out Flood Hazard Permit Application Package (PDF) including the following:

  • Application
  • Site Plan
  • Elevation Certificates

Shoreline Requirements
Some properties within the flood plains may have additional shoreline requirements. Please view our Shoreline Requirements page for additional information.

Additional Requirements

The flood hazard permit process includes preparation of a Floodplain Habitat Assessment and Mitigation (PDF) to evaluate development impacts in frequently flood areas. The assessment includes impacts to Listed Federally Endangered Species. A guidance document was prepared by FEMA Region X(10) to assist in preparation of a habitat assessment for project specific impacts. This habitat assessment should be prepared by a qualified consultant and submitted with your flood hazard permit application.

Survey Requirements

Elevation Certificates must be completed by a state licensed surveyor. Separate elevation certificates are required before, during and after construction. Initial elevations are taken prior to any earthwork and the final elevation certificate will be conducted once construction and final grading have been completed.