Floodplain Information

New Flood Hazard Zones

Updated Flood Insurance Rate Maps

The Federal Emergency Management Agency (FEMA) has prepared revised maps that identify new flood hazard zones within Boise. The city will be adopting these maps as well as updating floodplain regulations by June 2020. The map revisions reflect recent engineering studies and other updated information. The final maps will indicate where mortgage lenders may require flood insurance and where special development regulations may apply. Property owners are encouraged to review the revised flood maps.

Review Maps

Updated Flood Hazard Regulations

The City of Boise will be amending Chapter 11-08 (Flood Hazard Regulations) of the Development Code. The Federal Emergency Management Agency (FEMA) issued new Flood Insurance Rate Maps (FIRM(s) and a Flood Insurance Study (FIS) on December 19, 2019. The primary purpose of the amendment is to update the ordinance to reference these new studies. Along with referencing the new maps, additional definitions and language clarifying existing regulations is included. These elements of the amendment will ensure Boise remains eligible for participation in the National Flood Insurance Program (NFIP).

Learn More

Learn about the Flood Insurance Program

Bridge over the Boise River

The City of Boise participates in the National Flood Insurance Program due to the existence of significant flood threats related to the Boise River, foothills gulches and several intermittent stream channels on the upper bench. This web page provides information about the nature and location of flood potential in Boise, floodplain development regulations, availability of flood insurance, tips for how to be safe in the event of a flood and links to additional resources related to flooding and flood protection.


Flood Hazard Information

Extensive property damage and even loss of life can occur from flooding. Property owners in a designated Special Flood Hazard Area (SFHA) should make every effort to protect themselves and their property from flood loss.

  • If your property is located within a floodplain, the Planning and Development Services staff at (208) 608-7100 can provide additional useful information such as the depth of flooding in your area and a completed FEMA elevation certificate if one is available for your property.
  • Public Works Engineering staff are also available at (208) 608-7150 to provide limited on-site technical analysis of your property for purposes of determining how to protect it from flooding.

Online Mapping

Boise's Mapping System has floodplain boundary maps. Once the map opens, click on the "Zoning" folder to access the floodplain information. 

Planning & Development Services

Boise's planning staff can provide floodplain information. Call (208) 608-7100.

Ada County Emergency Management

Ada County Emergency Management has information and resources related to disasters and emergency preparedness.

Flood Hazards, Flood Insurance and Flood Protection in Boise

The Flood Insurance Rate Map (FIRM) for the City of Boise identifies properties within or in close proximity to special flood hazard areas (SFHA) that are subject to flooding. Floodplain areas associated with the Boise River and Boise River tributaries include foothills gulches such as Cottonwood Creek, Crane Creek, Hulls Gulch, Sand Creek (Stuart Gulch) and Squaw Creek. The Boise River and its tributaries, as well as the various foothills gulches, have all caused damaging flooding in past years and will inevitably do so again.

National Flood Insurance Program and Community Rating System
The City of Boise is an active participant in the National Flood Insurance Program (NFIP), which enables owners of property within floodplain areas to purchase flood insurance. The City also participates in the Community Rating System (CRS) Program, which rates the community's performance in administering the NFIP.

  • CRS Rating
    Boise currently has a CRS rating of 6, which qualifies City flood insurance policy holders with U.S. companies for a 20% reduction in their flood insurance premiums. Foreign insurance companies, such as Lloyds of London are not obligated to provide the discount. 
  • Community Outreach
    The City must re-certify its CRS Program annually in order to maintain its classification. One of the elements of re-certification is a community outreach program and that is the primary purpose of this webpage.

The City of Boise maintains copies of the current FIRM, which were effective February 19, 2003. Copies are available at the Planning and Development Services (PDS) department and at the public library. PDS staff can help determine whether or not specific properties are within a SFHA, or determine the estimated depth of flooding in an area.

Several documents on flood protection are on file at the Boise Public Library including "Homeowner's Guide To Retrofitting (Six Ways To Protect Your House From Flooding)."

Flood Insurance

Mortgage lenders generally require flood insurance for properties within a SFHA. Citizens that own property outright are not required to purchase flood insurance and some elect not to, primarily because of the cost of the insurance premiums. All properties within SFHA should be covered by flood insurance as the primary protection against loss of property from flooding.

Mitigating Flood Damage

In addition to purchasing flood insurance, there are physical improvements that can be made to mitigate the damage from flooding. In some cases, it may be financially feasible to raise or elevate a structure so that the lowest floor is above the base flood elevation. There are also methods for dry flood-proofing structures so that all portions of the building below the base flood elevation are made watertight. Certain properties may also have options of physically raising structure openings such as window wells or constructing berms around the foundation.

Contact Information

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