DFIRM Floodplain Maps

Definition & Purpose

Flood Insurance Rate Maps (FIRMs) are the official maps on which the Federal Emergency Management Agency (FEMA) has delineated special flood hazard areas and risk zones. They show the location of a property relative to special flood hazard areas, which is one of the factors determining flood insurance rates. More information on FIRMs is available at the floodsmart.gov website.


FIRMs are used by:

  • Citizens, insurance agents, and real estate brokers to locate properties and buildings in flood insurance risk areas.
  • Planning staff and building officials to administer floodplain management regulations and to mitigate flood damage.
  • Lending institutions and federal agencies to locate properties and buildings in relation to mapped flood hazards, and to determine if flood insurance is required when making loans for the purchase or construction of a building or for providing grants following a disaster.

Schedule for Adoption and Implementation on Hold

The Preliminary Digital Flood Insurance Rate Maps (DFIRMs) were released in 2010, but their adoption was put on hold pending FEMA's resolution of the levee analysis and mapping approach. In 2013, FEMA issued a new approach to mapping levees (see www.fema.gov, search "LAMP") which is now being tested in ten communities across the country. As that new policy is vetted through pilot projects, FEMA will move forward with other mapping projects that have been on hold, including the Coastal Study.


Both the current FIRMS and the Preliminary DFIRMs can be viewed at Snohomish County Planning and Development Services (PDS) and at a local Sno-Isle library. The current FIRMS are also available online through FEMA's Map Service Center

The Preliminary DFIRMs are a Geographic Information System (GIS) database of flood hazard information, which, when adopted, will align with the county's existing GIS databases for property and development information.