Flood Maps

Interactive Maps

Interactive maps can be found at the links below. Once you get to the map page, click on the blue question mark in the upper right corner for information. (It is recommended that you use Firefox, Chrome, or internet Explorer version 10 or higher in order to access the maps.) Click here for instructions on using and reading the flood maps.

Previous (2009) Flood Maps
Current (2015) Flood Maps

Flood Zones

Visit the flood zones page to learn more about the various flood zones and other components of the flood maps. 

Flood Map Updates

FEMA has conducted an in-depth, large-scale series of studies to re-examine flood hazards and related risks in the coastal communities including Portsmouth. This resulted in new a Flood Insurance Study (FIS) and associated Flood Insurance Rate Maps (FIRMs) that reflect up to date coastal flood hazard information. The new maps became effective on August 3, 2015.

As a result, property owners throughout the city have up to date, reliable and internet accessible information about their flood risk. Some residents and business owners will learn that their flood risk is designated as higher risk (or in some cases lower risk) than on the previous FIRM.

Letters of Map Change (LOMC)

If a property owner thinks their property has been inadvertently mapped in a Special Flood Hazard Area (SFHA), they may submit a request to FEMA for a Letter of Map Change (LOMC). A SFHA is defined as the area that will be inundated by the flood event having a 1 percent chance of being equaled or exceeded in any given year. A LOMC reflects an official revision/amendment to an effective Flood Insurance Rate Map. If the LOMC request is granted, property owners may be eligible for lower flood insurance premiums, or the option to not purchase flood insurance. Only FEMA can change the maps.

Property owners may also wish to contact the FEMA Map Information eXchange (FMIX), toll free at 1-877-FEMA-MAP (1-877-336-2627) for assistance with the LOMC process. Interested applicants can also apply for LOMCs online.

View a listing of currently effective LOMCs in Portsmouth.