What Is a CLOMR? Application, FEMA Review, and Insurance Impact

A Conditional Letter of Map Revision, or CLOMR, is FEMA’s written opinion on whether a proposed construction project in or near a floodplain would meet National Flood Insurance Program standards if built as designed. It does not change the official Flood Insurance Rate Map. It tells a developer, before a shovel goes in the ground, whether the finished project will qualify for a formal map revision later.¹

The authority sits in 44 CFR § 65.8, which lets a community, or someone working through their community, ask FEMA to review a proposed project and comment on whether it would justify a future map revision.² The letter typically covers bridges, culverts, levees, channel modifications, and large fill operations — anything that changes how water moves through an area. FEMA’s own glossary is careful about what the letter is not: it “does not revise an effective NFIP map, it indicates whether the project, if built as proposed, would be recognized by FEMA.”¹

When a CLOMR Is Required

Not every floodplain project needs one. Under 44 CFR § 65.12, the requirement is triggered when a proposed development would push Base Flood Elevations past what a community is allowed to permit on its own authority.³ Two situations trigger the filing.

Inside an adopted regulatory floodway, the standard is zero. If the project would cause any increase in flood levels during a base flood event, the community must obtain conditional approval before allowing construction. Not even a fraction of a foot of rise is permitted without FEMA’s sign-off.

Where a community has not adopted a regulatory floodway, the threshold is higher. A CLOMR is required if the project, combined with all other existing and anticipated development, would raise the base flood elevation by more than one foot at any point within the community.

Communities that allow encroachments beyond these limits without FEMA’s conditional approval risk falling out of compliance with the National Flood Insurance Program, which can affect residents’ access to federally backed flood insurance.³

CLOMR or CLOMR-F

FEMA issues a separate variant, the CLOMR-F, for projects whose whole purpose is placing fill to raise land above the base flood elevation and remove it from the Special Flood Hazard Area. A standard CLOMR addresses hydraulic modifications — projects that change how water moves. A CLOMR-F addresses projects that change the ground itself. Documentation, engineering analysis, and fees differ between the two, so identifying which track applies is the first decision.⁴

What Goes Into the Application

The application is built around FEMA’s MT-2 forms package.⁵ Form 1 identifies the project, the affected community, and the type of revision requested, and must be signed by the applicant, the certifying engineer, and each community official affected. Form 2 documents the hydrologic and hydraulic analyses. Form 3 covers the engineering specifications for any structures — bridges, culverts, levees — included in the project.

Alongside the forms, the applicant submits a certified topographic work map, proposed or as-built plans certified by a registered Professional Engineer, a narrative describing the project’s purpose and methodology, and all hydrologic and hydraulic analyses in digital format.⁶⁷⁸ Using an unapproved model is grounds for rejection. Incomplete packages are the most common reason applications stall, because FEMA will not begin its review until the submittal is deemed adequate.

Endangered Species Act Documentation

Every CLOMR application must include documentation showing compliance with the Endangered Species Act, and this requirement catches many applicants off guard.⁹ Projects with federal funding, construction, or permitting can rely on the federal agency’s Section 7 consultation: a “No Effect” determination, a “Not Likely to Adversely Affect” determination with concurrence from the U.S. Fish and Wildlife Service or National Marine Fisheries Service, or a biological opinion with a “no jeopardy” finding.

Purely private projects work differently. If the developer determines there is no potential for harm to listed species, that determination stands on its own and no federal agency concurrence is required. If there is potential for harm, the developer must redesign the project after consulting with the wildlife services or obtain an Incidental Take Permit.

Notifying Affected Property Owners

The applicant must document that individual legal notice went to all property owners affected by the proposed changes, both inside the community and in neighboring areas.³ If the project reaches into more than one community, each community’s chief executive officer must also concur. Raising flood elevations in one place can shift risk, insurance costs, and building restrictions onto neighbors who had no voice in the design, which is why the notice requirement exists.

Review Fees

FEMA charges a flat fee before starting its review, and under 44 CFR Part 72 the fee is non-refundable once work begins, even if the application is ultimately denied.¹⁰ The current schedule has been in place since February 2015:¹¹

CLOMR based on hydrology, bridges, culverts, channels, or a combination: $6,500 online, $6,750 by paper form.
CLOMR based on levees, berms, or other structural measures: $7,000 online, $7,250 by paper, plus $60 per hour for any review time exceeding the base.

The hourly surcharge on structural reviews can add up on complex levee projects. Payment must accompany the application; FEMA will not begin work without it.

How FEMA Reviews the Application

Once FEMA receives a complete application with payment, the review follows the timeline in 44 CFR Part 72. FEMA has 60 days to notify the applicant and the community whether the submittal is adequate — whether it contains enough information for a technical review to proceed. If there are gaps, the package goes back for corrections and the review clock does not start until the deficiencies are resolved.¹⁰

After FEMA deems the submittal adequate, it has 90 days to issue the CLOMR or provide preliminary copies of revised flood map panels for review and comment. In practice, complex projects, particularly those involving levees or multiple communities, often take longer than the regulatory target. The 90 days runs from receipt of adequate information, not from the date of initial submission, which matters for project scheduling.

If FEMA Denies the Request

FEMA can deny a CLOMR outright under 44 CFR § 72.6, or issue a determination with specific comments, concerns, or conditions about the project’s design and its flood hazard impacts. Denied applicants are not entitled to any refund of fees already paid.¹⁰ The developer can revise the design to address the concerns and resubmit, but that means paying the review fee again and restarting the process. Getting the hydraulic modeling right on the first pass is far cheaper than paying for multiple rounds.

After Construction: The Final LOMR

A CLOMR is not the finish line. Once construction is complete, the community must request a formal revision to the Flood Insurance Rate Map by submitting as-built certification and supporting data.¹ The as-built plans must be certified by a registered Professional Engineer confirming the project was built in accordance with the approved design.⁶ That step converts the conditional approval into a Letter of Map Revision (LOMR), which actually changes the official map.

Skipping the follow-through is a common mistake. Without the final LOMR, the official map still shows the pre-construction flood zone. Property owners remain in the Special Flood Hazard Area for insurance purposes, lenders keep requiring flood insurance at the higher-risk rate, and the community’s floodplain records don’t match what was built. The CLOMR gives permission to build. The LOMR is what changes the map.

What a CLOMR Means for Insurance

A CLOMR provides financial certainty for the developer, but it does not reduce flood insurance premiums for anyone. The existing Flood Insurance Rate Map remains the legal standard for insurance requirements and real estate transactions until FEMA issues the final LOMR.¹ Throughout the construction period, properties in the project area stay in whatever zone they were in before.

For lenders, a CLOMR signals that flood zone designations may change later, but current mandatory purchase requirements are unaffected. A borrower whose property sits in a Special Flood Hazard Area still needs flood insurance regardless of whether a CLOMR has been issued. Only after the final LOMR is issued and the map officially changes can property owners apply for reduced coverage or removal of the insurance mandate, depending on their new zone.

1
FEMA.gov. Conditional Letter of Map Revision (CLOMR)
2
eCFR. 44 CFR 65.8 – Review of Proposed Projects
3
eCFR. 44 CFR 65.12 – Revision of Flood Insurance Rate Maps to Reflect Base Flood Elevations Caused by Proposed Encroachments
4
FEMA.gov. Letter of Map Amendment and Letter of Map Revision-Based on Fill Process
5
FEMA.gov. MT-2 Application Forms and Instructions
6
Federal Emergency Management Agency. Instructions for Completing the Application Forms for Conditional Letters of Map Revision and Letters of Map Revision
7
FEMA.gov. Hydraulic Numerical Models Meeting the Minimum Requirement of National Flood Insurance Program
8
FEMA.gov. Hydrologic Numerical Models Meeting the Minimum Requirement of National Flood Insurance Program
9
FEMA.gov. Required Endangered Species Act Compliance Documentation for Conditional Letter of Map Revision Requests
10
eCFR. 44 CFR Part 72 – Procedures and Fees for Processing Map Changes
11
Federal Emergency Management Agency. Flood Map-Related Fees