Flood Hazard Areas

Floodplains are areas of land susceptible to inundation by floodwaters. Special Flood Hazard Areas (SFHA) are flood plains that adjoin a river, stream, or other inland or coastal waterway that are inundated by water during the 1 percent annual chance flood (100-year flood). The 1 percent annual chance flood is a flood event having a 1 percent chance of being equaled or exceeded in magnitude in any given year.

SFHAs are considered a Wetland Resource Area under the Massachusetts Wetlands Protection Act and are depicted on Federal Emergency Management (FEMA) Flood Insurance Rate Maps (FIRM) as Zones A, AE, AH, AO, AR, A99, V and VE.

Questions?  Contact the Floodplain Manager

Changes to Flood Insurance and Maps

Changes to the Flood Insurance Rate Maps for the City of Boston go into effect on March 16, 2016.

The Federal Emergency Management Agency (FEMA) has been revising flood maps to reflect current flood risks in coastal areas nation-wide over the last few years. The revisions use historical data and advanced modeling technology to more accurately determine current flood risks. The revised maps do not account for future flooding risks. The official map of a community and its flood hazards is known as a Flood Insurance Rate Map (FIRMs).

The revised maps provide more information about flood risks for new and existing development. Boston adopts these maps so property owners can qualify to purchase and maintain federally subsidized flood insurance through the National Flood Insurance Program (NFIP). The City of Boston is also eligible to receive federal disaster assistance in the case of a flood emergency by adopting the FIRMs.

The updated FIRMs for Boston are available at the FEMA Map Service Center and will go into effect on March 16, 2016. For assistance in understanding the FEMA FIRMs, and to find out if your property will be affected by remapping, see the FEMA MSC How-to guide here and read the resources below.

Open Houses

FEMA Corps are holding Flood Maps Tabling at the following Boston Public Libraries:

  • East Boston branch, 365 Bremen St, Boston, MA 02128
    Every Monday, 2:30pm to 5:00pm

  • Charlestown branch, 179 Main St, Charlestown, MA 02129
    Every Tuesday, 2:30pm to 5:00pm

  • South Boston branch, 646 East Broadway, South Boston, MA 02127
    Every Thursday, 2:00pm to 4:00pm

  • West End branch, 151 Cambridge St, Boston, MA 02114
    Every Friday, 2:00pm to 4:00pm

These events are weather dependent. To confirm, call 617-635-4258.


  • FEMA Updated Flood Maps Open House: Learn about the new flood zones for the City of Boston, and receive one-on-one assistance in understanding if you will be affected by the flood map changes. Open House is on January 12 in Dorchester.

  • Ready.Gov: View everything from educational information about flooding to tips on making an emergency kit.

  • FloodSmart.gov: Find resources on understanding flood maps, defining flood risks, the cost of flooding, and more from the National Flood Insurance Program.

  • MA Homeowners Handbook for Coastal Hazard Prep: Learn how to prepare for storms with information provided by Sea Grant.

Federal Emergency Management Agency (FEMA)

FEMA provides basic flood insurance information for claims adjusters, property owners, insurance professionals, lenders, both state and local officials, and surveyors.

Office of Coastal Zone Management Stormsmart Coast

The StormSmart Coasts program is designed to:

  • Assist communities and people working and living on the coast by providing information, strategies, and tools to help address challenges arising from erosion, flooding, storms, sea level rise, and other climate change impacts; and

  • Promote effective management of coastal landforms, such as beaches and dunes.

Their publications include materials on coastal erosion, flooding, storms, and sea level rise, as well as other publications on coastal geology.

FEMA Map Update Resources

  • The National Flood Insurance Program (NFIP)

    The NFIP is a federal program that mandates flood insurance for any structure located in a high-risk area (the 100-year floodplain) that has a federally backed mortgage on the property. It also makes flood insurance available to all property owners, renters, and businesses in communities that join the NFIP.

    When floodmap changes occur, the NFIP provides lowe-cost flood insurance options known as "grandfathering". For more information on the Grandfathering Rule, please refer to the FEMA Grandfathering Factsheet and the FloodSmart factsheet.

    More Information about the NFIP

  • The Biggert-Waters Flood Insurance Reform Act of 2012 (BW-12)

    In July 2012, the US Congress passed the Biggert-Waters Flood Insurance Reform Act of 2012 (BW-12) which requires the NFIP to raise rates to reflect true flood risk, make the program more financially stable, and change how Flood Insurance Rate Map (FIRM) updates impact policyholders.

    Flood Insurance Reform Act of 2012

  • Impacts to My Property

    To find out how your property will be affected by FEMA's remapping process and the Flood Insurance Reform Act of 2012, please contact your insurance provider directly. He or she is the only person who can answer questions about your property and your policy.