If You Disagree with the Preliminary Flood Maps

Mapping Project Phases Once Preliminary Maps Are Issued

Flood Mapping Project Phases

When a preliminary flood map is issued and you disagree with the new flood risk identified for your property, there are two ways to try to amend it:

  • Appeal or Comment – This is a formal process which occurs after the preliminary flood maps are released, but before the final ones are issued (shown below as the 90-day Appeal Period).  
  • Appeal Period - This period is April 30 - July 28, 2021.

  • Letter of Map Change – A property owner can submit a request for Letter of Map Change (LOMC), which if approved, will officially change the flood risk around a building from a high-risk area to a moderate-low risk area.  This typically reduces the cost of flood insurance.  This opportunity occurs after the new flood map becomes effective. 

These two processes are described below:


When a new preliminary flood map is released, some residents, business owners, developers and others may disagree with how they are affected.  FEMA provides for a 90-day Appeal and Comment Period when new or revised Base Flood Elevations (BFEs) are determined, or flood hazard zones or floodway boundaries change.  Property owners, developers and others have opportunities to submit evidence on why they believe their property has been improperly mapped. However, it must be scientifically or technically based, not just “it hasn’t flooded in a while (or ever).” 

During the 90-day Appeal and Comment Period, they can submit:

  • An Appeal –  which is a formal written objection to the addition/modification of the BFE, Special Flood Hazard Area (SFHA), floodway, or flood zone change and which requires analysis or scientific evidence showing the information on the preliminary product is scientifically or technically incorrect.
  • A Comment – which is an objection to any other information related to the new map that is not an Appeal.

Note that Appeals and Comments should be forwarded to the District who will review them and forward them on to FEMA for review and resolution.  During its review, FEMA will evaluate the submitted data and request additional data, as necessary. Once FEMA issues the appeal resolution, FEMA transmits the appeal resolution letter to the District and all appellants and makes any revisions to the preliminary FIRM, as appropriate. Once all appeals and comments are resolved, the flood map is finalized and a Letter of Final Determination is then sent to each community stating that the flood map will become effective in six months.


Due to map scale limitations, property owners with individual lots or structures believed to be incorrectly shown within the high-risk area (Zone A, known as a Special Flood Hazard Area, or SFHA) on the preliminary flood map may submit mapping and survey information to FEMA to request a Letter of Map Amendment (LOMA), or Letter of Map Revision Based on Fill (LOMR-F), which officially changes the flood zone from a high-risk Zone A to a moderate-low risk Zone X when the new maps become effective. 

While this process may also remove the Federal Mandatory Purchase Requirement when they become effective – and your lender may no longer require flood insurance – it does not mean the risk of flooding has been removed; it is only reduced.  You are strongly encouraged to continue to carry flood insurance with the lower-cost Preferred Risk Policy.  More than 30% of flood claims in Arizona come from policyholders in moderate-low risk flood zones.

For more information on LOMAs and LOMR-Fs, visit these resources: