These are FEMA letters of map change. They amend or comment on the Flood Insurance Rate Map. They are not building permits. They are not no-rise certifications. People use the acronyms as if they were interchangeable. They are not.
LOMA — Letter of Map Amendment
A LOMA is FEMA agreeing that a structure or lot was mapped into the Special Flood Hazard Area on natural ground that is actually at or above the base flood elevation. You are saying the map is wrong about that property, not that you filled it.
You typically need a licensed surveyor or engineer and an elevation certificate: lowest adjacent grade (for a structure) or the lowest lot elevation (for a whole lot) versus the BFE. If FEMA agrees, the letter removes that structure or lot from the SFHA for insurance and lender purposes. It does not rewrite the FIRM panel for the neighborhood.
LOMR-F — Letter of Map Revision Based on Fill
Same idea after someone placed fill. Lowest adjacent grade (and, for a lot, the lowest lot elevation and lowest floor) have to be at or above the BFE. The community also has to find the site “reasonably safe from flooding.” Fill in a floodway is a different, harder problem — that is usually a no-rise or a CLOMR, not a LOMR-F.
LOMR — Letter of Map Revision
A LOMR revises the effective FIRM: floodplain boundary, floodway, BFE, or a combination. It is based on better data, a completed project, or as-builts after a CLOMR. When it becomes effective, the map changes. That is the letter you want after you actually moved a channel or built the levee FEMA already commented on.
A LOMR that raises BFEs or expands the SFHA has notice and appeal steps. It is not a weekend errand.
CLOMR — Conditional Letter of Map Revision
A CLOMR is FEMA’s comment that a proposed project, if built as shown, would qualify for a LOMR. It does not change the map. It does not authorize construction by itself. The community still issues (or withholds) the floodplain development permit. After you build, you submit as-builts for the LOMR.
If a floodway project cannot show a no-rise, 44 CFR 60.3(d)(4) is the CLOMR path. Encroachment in AE without a floodway that would raise the BFE more than one foot is also a CLOMR conversation (44 CFR 60.3(c)(13) / 65.12).
Which letter you actually need
- Mapped in by a bad contour, structure already high: LOMA.
- You filled the pad and want it out of the SFHA: LOMR-F.
- You changed (or will change) the floodplain or floodway on the map: CLOMR then LOMR, or LOMR if the work is already done and the data are better.
- You are in the floodway and the model holds 0.00: no-rise, not a LOMA.
None of these replace local floodplain permits, elevation, or state 401 / coastal rules. None of them are a 404 JD.
How we use it
We tell you which letter matches the fact pattern, what survey and model FEMA will want, and whether the request is worth making. Sometimes the cheapest answer is elevate and stay on the map. Sometimes a LOMA is obvious. We do not write “FEMA will take you out” on a proposal until the grades exist.
Cypress Environment & Infrastructure works from Biloxi, Mobile, and Pensacola, throughout the Southeastern US. Office hours are Monday–Friday, 9 a.m.–5 p.m.
See flood zones and base flood elevation and What is a floodplain?.