Understanding Levees and the NFIP
Levees are man-made structures—usually earthen embankments—designed to contain, control, or divert the flow of water to provide protection from temporary flooding. In the context of the National Flood Insurance Program (NFIP), levees play a critical role in determining whether a community is considered part of a Special Flood Hazard Area (SFHA). While levees are built to reduce risk, they do not eliminate it entirely. For insurance professionals, understanding how FEMA evaluates these structures is essential for explaining coverage requirements to clients.
The relationship between a levee and flood insurance is primarily governed by the concepts of certification and accreditation. When a levee is properly maintained and meets specific federal standards, the land behind it is often mapped as a moderate-to-low risk zone. However, if a levee fails to meet these standards, the resulting remapping can have significant financial implications for property owners. For more foundational knowledge, see our complete Flood exam guide.
Certification vs. Accreditation
| Feature | Levee Certification | Levee Accreditation |
|---|---|---|
| Primary Purpose | Technical engineering verification. | Administrative mapping decision. |
| Responsible Party | Licensed Professional Engineer or Federal Agency. | FEMA. |
| Focus | Design, operation, and maintenance standards. | Inclusion on a Flood Insurance Rate Map (FIRM). |
| Impact on Insurance | Prerequisite for accreditation. | Determines if the area is an SFHA (Zone A/V) or Zone X. |
The Mandatory Purchase Requirement
One of the most significant impacts of a levee's status is the Mandatory Purchase Requirement. If a levee is accredited by FEMA, it is shown on a Flood Insurance Rate Map (FIRM) as providing protection against the base flood (the 1-percent-annual-chance flood). Consequently, the area behind the levee is mapped as a moderate-risk zone, typically labeled as Zone X (shaded).
In Zone X (shaded), flood insurance is not federally mandated for properties with mortgages from federally regulated lenders. However, if a levee is not accredited—meaning it does not meet the requirements of 44 CFR Section 65.10 of the NFIP regulations—the area is mapped as a high-risk Special Flood Hazard Area (SFHA), usually Zone A or AE. In these zones, flood insurance is mandatory for most mortgaged properties. You can test your knowledge of these zone requirements with our practice Flood questions.
Levee Status and Risk Perception
Provisionally Accredited Levees (PAL)
When FEMA updates flood maps, they may encounter levees that were previously accredited but no longer have the full documentation required to prove they meet current standards. To prevent an immediate and potentially disruptive change in insurance requirements, FEMA may designate these as Provisionally Accredited Levees (PALs).
The PAL designation is a temporary status. It allows a community or levee owner a specific timeframe to find and submit the necessary data and documentation to show the levee still provides base flood protection. During this provisional period, the area behind the levee remains mapped as a moderate-risk zone, and the mandatory purchase requirement is not yet triggered. If the documentation is not provided within the allotted window, the levee is de-accredited, and the area is remapped as an SFHA.
Risk Rating 2.0 and Levees
Frequently Asked Questions
No. FEMA does not build, own, or maintain levees. Levees are typically built and maintained by local communities, levee districts, or the U.S. Army Corps of Engineers. FEMA's role is solely to evaluate whether a levee meets the standards for mapping purposes.
If a levee is de-accredited, the area behind it is remapped into an SFHA. This usually triggers the mandatory purchase requirement for federally backed mortgages. While premiums may increase, the NFIP often provides 'Newly Mapped' transition rates to help property owners adjust to the higher costs over time.
No. No levee provides full protection against all possible flood events. Levees can be overtopped by water levels higher than they were designed to handle, or they can fail due to structural issues. FEMA and insurance agents strongly recommend that property owners behind levees maintain flood insurance even if it is not mandated.
This is the specific section of the Code of Federal Regulations that outlines the criteria FEMA uses to determine whether a levee can be accredited. It includes requirements for design (freeboard), structural stability, and an operation and maintenance plan.