Understanding FEMA Letter of Map Change (LOMCs) Types
FEMA’s Flood Insurance Rate Maps (FIRMs) are the regulatory foundation for flood insurance requirements and development compliance within the National Flood Insurance Program (NFIP). However, FIRMs often require clarification or revision, either due to mapping inaccuracies at the parcel level or proposed projects that alter hydrologic and hydraulic conditions.
To address these scenarios, FEMA issues Letters of Map Change (LOMCs). These determinations fall into two broad categories: conditional (for proposed projects) and official (which amend the effective map).
Types of LOMCs
Conditional Letter of Map Amendment (CLOMA)
A CLOMA is FEMA’s review of a proposed structure or project to determine if, when built as designed, it would be located outside the Special Flood Hazard Area (SFHA). CLOMAs do not amend the effective FIRM but provide advance assurance for future LOMA requests.
Conditional Letter of Map Revision (CLOMR)
Required when a proposed project will impact hydrology or hydraulics, a CLOMR evaluates whether alterations—such as channel modifications, encroachments, or grading—would justify future changes to Base Flood Elevations (BFEs), floodways, or SFHA boundaries. While not regulatory, it provides FEMA’s preliminary determination prior to construction.
Conditional Letter of Map Revision Based on Fill (CLOMR-F)
For projects involving placement of fill, a CLOMR-F assesses whether the fill, if placed as proposed, would elevate land sufficiently to warrant removal from the SFHA. This is particularly relevant for subdivisions, large-scale developments, or commercial sites seeking insurance and compliance certainty pre-construction.
Letter of Map Amendment (LOMA)
A LOMA is FEMA’s official amendment to the effective FIRM based on site-specific elevation data. LOMAs are commonly requested by property owners to demonstrate that a structure or parcel is above the BFE, thereby removing the mandatory flood insurance requirement under federal law.
Letter of Map Revision (LOMR)
A LOMR is a formal revision to the effective FIRM that incorporates updated hydrologic, hydraulic, or topographic data. LOMRs may adjust BFEs, delineate new floodplain or floodway boundaries, or otherwise refine the regulatory flood risk data. They carry the same legal and regulatory weight as the original FIRM upon issuance.
Letter of Map Revision Based on Fill (LOMR-F)
When fill has been placed and certified elevation data confirms the parcel or structure is above the BFE, a LOMR-F provides FEMA’s official determination of removal from the SFHA. This is particularly relevant for compliance, insurance underwriting, and marketability of developed parcels.
Accuracy and Support Are Key
For stakeholders in real estate finance and development, understanding the distinctions between these LOMC types is critical. Each carries different implications for insurance requirements, closing timelines, underwriting risk, and compliance with NFIP regulations.
WTGs team ensures accuracy, thereby minimizing delays and losses, because we are staffed with qualified professionals, like Certified Floodplain Managers (CFMs) who cantdetermine eligibility, gather required documentation, and submit to FEMA.
LOMCs are more than just administrative letters—they are regulatory instruments that directly affect insurability, marketability, and compliance. WTG specializes in navigating these processes to help lenders, investors, and title professionals achieve clarity and efficiency in flood risk management.
The information provided is for informative purposes only and is not intended to be legal advice or a legal opinion. For legal advice, please consult an attorney.
