Map Amendments and Revisions

Landowners often ask how to request a change to the FEMA flood zone designation for their property or structure. FEMA has administrative procedures to request changes to the FEMA flood designation for single or multiple lots based on more accurate elevation data or updated technical data.

The two main options for property owners to request zone flood changes are:

  • Letter of Map Amendments (LOMA) – a document from FEMA confirming the structure (or property) is on natural ground that is above the Base Flood Elevation (BFE) based on more accurate elevation documentation; the flood zone designation is changed to a lower risk zone
  • Letter of Map Revisions based on Fill (LOMR-F) – A document from FEMA confirming the structure (or property) has been elevated on fill and meets (or will meet) local floodplain regulations (including meeting lowest floor elevation requirements; the flood zone designation is changed to a lower risk zone
See more details on how to request FEMA flood zone designations below.

Changes to the effective FEMA map - Actual changes to the effective FEMA map are called a Letter of Map Revision (LOMR). Requests for LOMRs require data prepared by Professional Engineers or Licensed Surveyors, and the procedures are much more complicated, costly, and lengthy. See more details about LOMRs below.

Letters of Map Amendments

A Letter of Map Amendment (LOMA) is a letter from FEMA confirming that a portion of the map is incorrect. For an individual lot (or multiple lots) where a structure is shown in the flood hazard area on FEMA's floodplain maps and the flowing are valid:

  • Either
    1. Better elevation information shows the structure is higher than the Base Flood Elevation (BFE), or 1% annual chance flood elevation, or
    2. A better aerial photo or other information shows the structure is not actually "in" the flood hazard area. This is also referred to as a Letter of Map Amendment - Out as Shown (LOMA-OAS)
  • No fill has been placed to elevate the building or adjacent to the building (after the date of the first FEMA floodplain map showing the structure in a flood hazard area)

When to pursue a LOMA?

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structure eligible for loma since lowest adjacent grade is higher than the base flood elevation
Eligible for LOMA. The Lowest Adjacent Grade is higher than the Base Flood Elevation.

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structure eligible for loma, even if the structure has a basement
Eligible for LOMA, even if the structure has a basement, if the Lowest Adjacent Grade (LAG) is higher than the Base Flood Elevation (BFE). Only eligible if no fill has been placed after the first FEMA floodplain map showing that site in a floodplain.

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structure not eligible for loma since the lowest adjacent grade is below the base flood elevation
Not eligible for LOMA. The Lowest Adjacent Grade would be at the lowest support for the deck or stairway. Since the Lowest Adjacent Grade is below the Base Flood Elevation the structure is not eligible. It would be eligible if the deck is removed or detached from the house.

Types of Letters of Map Amendments

Traditionally, the application for most LOMAs include a field survey to verify the Lowest Adjacent Grade (LAG) is above the Base Flood Elevation (BFE). However, there are a couple of abbreviated methods which can be utilized depending on the scenario

  • Letter of Map Amendment - Out as Shown (LOMA-OAS) would be used when a GIS-based floodplain map overlaid on top of an aerial photo plainly shows that a structure is completely out of the floodplain. This method would require some form of elevation data for the structure.
  • Letter of Map Amendments using LiDAR utilizes a streamlined method for elevation data in Minnesota.
  • eLOMAs are available to licensed surveyors and PEs, and offers an opportunity to get a LOMA from FEMA in less than a day. This option is available for detailed study areas and A Zones where more accurate Base Flood Elevations have been determined.
  • Conditional Letter of Map Amendments (CLOMA) would be used to show that a 100-year flood if built as proposed.
There is no fee for FEMA to review a LOMA. However, there will likely be costs associated with obtaining the data needed, or for assistance completing the application. If any part of the structure or lot requested to be removed from the FEMA mapped floodplain is in the floodway, a community official will be required to sign a Community Acknowledgement Form.

Letter of Map Revision Based on Fill

A Letter of Map Revision Based on Fill (LOMR-F) is for individual or multiple lots when there has been fill placed to elevate the building or adjacent to the building (after the date of the first FEMA floodplain map showing the structure in a floodplain).

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structure eligible for lomr-f
To be eligible for a LOMR-F:

  1. the lowest natural ground touching the building (including decks and stairway supports) is above the base flood elevation (BFE) and
  2. the lowest floor (including basement or crawl space) is above the base flood elevation (BFE).
There is a $425 fee for FEMA to review the LOMR-F application. This is in addition to any costs associated with obtaining the data needed, or for assistance completing the application packet.

Conditional Letter of Map Revision based on Fill

A Conditional Letter of Map Revision based on Fill (CLOMR-F) is used to show that a proposed structure that is to be elevated on fill would not be inundated by the 100-year flood if fill is placed on the parcel as proposed or the structure is built as proposed.

Letters of Map Revisions (LOMRs)

A Letter of Map Revision (LOMR) is a letter from FEMA officially revising the Flood Insurance Rate Map (FIRM) or Flood Insurance Study (FIS) to show changes to floodplains, floodways, or flood elevations.

LOMRs are often completed when there is a proposed project that changes the circumstances in a watershed or stream. A CLOMR is used to show that a proposed project would be eligible for a LOMR (or physical map revision) once the project is constructed.

Examples of projects that may require a LOMR:

  • Projects that affect or change watershed hydrology - such as a dam, diversion channel, or detention basin
  • Projects that affect or change stream hydraulics - such as channelization, new bridges or culverts, or levees
  • Projects that change topographic conditions in the floodway - such as grading or filling
  • Projects that change the floodway boundary such as stream realignment
  • LOMRs may be completed if there are errors in the effective FIRM or FIS or if there is better available data that can be incorporated into the FIRM or FIS, but they are not required.
Changes in watershed hydrology require an additional review by the Interagency Hydrology Review Committee (IAHRC) in addition to the LOMR or CLOMR review by FEMA and the MnDNR. If a proposed project will change watershed hydrology for a FEMA modeled and mapped stream, contact the DNR for guidance on submitting information to the IAHRC.

See the MnDNR’s LOMR/CLOMR Guide for in-depth guidance on requirements and application procedures for LOMRs and Conditional LOMRs (for projects that are proposed, but not constructed).

Apply for a LOMA, LOMR-F or LOMR

Paper

  • MT-EZ Form - For Single Lot Letters of Map Amendment, no fill involved
  • MT-1 Forms - For Multi-Lot Letters of Map Amendment and Letters of Map Revision Based on Fill
  • MT-2 Forms - For changes to FIRMs based on updated data or changes to the Base Flood Elevation or floodway.

Online

  • Online Letter of Map Change (LOMC) application - For LOMAs, LOMR-Fs and LOMRs:
    • Can be used by anyone, including landowners. Alternative to filling out and mailing the paper MT-EZ, MT-1 or MT-2 forms and attachments and is processed faster.
  • eLOMA - For LOMAs
    • Available to licensed surveyors and professional engineers only. Can only be used for LOMAs (not LOMR-Fs or LOMRs) where there is detailed Base Flood Elevation data. Can be processed in a matter of minutes.

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