Coastal Barrier Resources System: Frequently Asked Questions

What is the Coastal Barrier Resources System?

The Coastal Barrier Resources Act (CBRA) of 1982 established the John H. Chafee Coastal Barrier Resources System John H. Chafee Coastal Barrier Resources System
Learn more about the John H. Chafee Coastal Barrier Resources System, which was established under the Coastal Barrier Resources Act in 1982.

Learn more about John H. Chafee Coastal Barrier Resources System
(CBRS), a defined set of relatively undeveloped coastal barrier units located along the Atlantic, Gulf of Mexico, Great Lakes, U.S. Virgin Islands, and Puerto Rico coasts. These areas are delineated on a set of maps that are enacted into law by Congress and maintained by the Department of the Interior through the U.S. Fish and Wildlife Service (Service). Most new federal expenditures and financial assistance are prohibited within the CBRS. The prohibition that is most significant to property owners is the denial of federal flood insurance through the National Flood Insurance Program (NFIP) for structures constructed or substantially improved after designation within the CBRS. CBRA does not prohibit development, and it imposes no restrictions on development conducted with non-Federal funds. Congress enacted CBRA to minimize the loss of human life, wasteful federal expenditures, and damage to the natural resources associated with coastal barriers coastal barriers
Learn more about coastal barrier landforms.

Learn more about coastal barriers

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Where are the CBRS units located?

CBRS units are located in 23 states and territories along the Atlantic, Gulf of Mexico, Great Lakes, U.S. Virgin Islands, and Puerto Rico coasts. There are no CBRS units along the Pacific coast. View the official CBRS maps.

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What are the differences between System Units and Otherwise Protected Areas?

The CBRS contains two types of units, System Units and Otherwise Protected Areas (OPAs). OPAs are denoted with a "P" at the end of the unit number (e.g., FL-64P, P10P).

System Units are generally comprised of private lands that were relatively undeveloped at the time of their designation within the CBRS. The boundaries of these units are generally intended to follow geomorphic, development, or cultural features. Most new federal expenditures and financial assistance, including flood insurance, are prohibited within System Units.

OPAs are generally comprised of lands held by a qualified organization primarily for wildlife refuge, sanctuary, recreational, or natural resource conservation purposes. The boundaries of these units are generally intended to coincide with the boundaries of conservation or recreation areas such as state parks and national wildlife refuges. The only federal spending prohibition within OPAs is on flood insurance.

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What is a CBRS property determination?

A "CBRS property determination" is an official letter from the Service that indicates whether a specific property or project site is located within or outside of the CBRS. The Service only provides such determinations for properties that are within 20 feet of a CBRS boundary (i.e., areas within the “CBRS Buffer Zone” depicted in the CBRS Mapper). This includes structures bisected by the boundary. All other locations should be verified using the CBRS Validation Tool

The Service's determination is based upon materials provided by the requester and the official CBRS map of the area. The Service's response letter contains an in/out determination and the prohibition date for federal flood insurance if the property is located within the CBRS. 

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Who is authorized to make official CBRS property determinations?

Official CBRS determinations are made only by the Service.

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Who should I contact to request a CBRS property determination?

All interested parties, except insurance agents, may submit property determination requests for locations within the CBRS Buffer Zone directly to the Service’s Headquarters Office at Insurance agents should send requests for CBRA determinations to the NFIP Direct Servicing Agent, or NFIP Write Your Own insurer to whom application for flood insurance coverage is being made. The insurer will send the request to the NFIP Bureau, who will in turn submit the case to the Service for an official determination.

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What materials should I submit to the Service for a CBRS determination?

In order for the Service to make a property determination, the requester should submit a valid address along with the output from the CBRS Validation Tool indicating that the location is within the CBRS Buffer Zone. The requestor should also submit any additional documentation necessary to help the Service positively confirm the location of the property, such as a map showing the location of the property, a property record card, survey, deed, and/or elevation certificate. If sufficient information to complete the determination is not submitted, additional information will be requested and the request will be put on hold until the necessary information is received.

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Is there a fee associated with CBRS determinations?

No. The Service does not charge a fee to process CBRS determinations.

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How does the Service make a CBRS determination?

The submitted materials are examined and the location of the property in question is confirmed, often using online resources such as property records and mapping tools provided by the local government. The property is then located in relation to the CBRS boundaries using digital parcel data, a plat or tax map, and/or aerial imagery, along with the official CBRS map for the area in question. The Federal Emergency Management Agency's Flood Insurance Rate Maps are not used to determine the placement of the CBRS boundary for official CBRA determinations.

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How long does it take to make a CBRS determination?

It generally takes two to three weeks to complete a CBRS determination. The turn-around time depends on the staff resources available at the time and the CBRA Program's pending workload.

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Are some structures located within the CBRS eligible for federal flood insurance?

Federal flood insurance is available within the CBRS if the subject structure structure
Something temporarily or permanently constructed, built, or placed; and constructed of natural or manufactured parts including, but not limited to, a building, shed, cabin, porch, bridge, walkway, stair steps, sign, landing, platform, dock, rack, fence, telecommunication device, antennae, fish cleaning table, satellite dish/mount, or well head.

Learn more about structure
was constructed (or permitted and under construction) before the CBRS area's flood insurance prohibition date flood insurance prohibition date
A flood insurance prohibition date refers to the date on which the prohibition on Federal flood insurance first took effect for a given area. The Federal Emergency Management Agency’s National Flood Insurance Program uses this date to determine whether a structure located within the CBRS is eligible for Federal flood insurance. Federal flood insurance is available within the CBRS for structures that were constructed (or permitted and under construction) before the area’s flood insurance prohibition date (which is generally tied to the date that the area was first established as either a System Unit or OPA, but may differ in some cases). If an existing insured structure within the CBRS is substantially improved or damaged (i.e., more than 50 percent of the structure’s market value), its Federal flood insurance policy cannot be renewed).

Learn more about flood insurance prohibition date
(which is included in the Service's CBRS determination letter and shown in the CBRS Mapper). If an existing insured structure within the CBRS is substantially improved or damaged (i.e., over 50 percent of the structure's market value), the federal flood insurance policy cannot be renewed. For structures located within an OPA, federal flood insurance may be available (regardless of the date of construction) if written documentation is provided certifying that the structure is used in a manner consistent with the purposes for which the area is protected (e.g., restroom facilities, visitors center, employee housing within a park).

The NFIP has a Flood Insurance Manual (FIM) which is used primarily by insurers and agents selling and servicing federal flood insurance. The FIM contains information regarding flood insurance eligibility for structures located within the CBRS and should be consulted prior to writing a flood insurance policy that may be affected by CBRA.

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What happens if a federal flood insurance policy is issued within the CBRS in error?

If a federal flood insurance policy is issued within the CBRS in error, it must be cancelled and the premium refunded; no claim can be paid, even if the error is not found until after a loss.

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Is there an appeals process for CBRS determinations?

There is not an official appeals process, however, interested parties may submit new information to the Service and ask for a reevaluation if they believe a CBRS determination is incorrect. If the location of the property has been correctly determined in relation to the CBRS boundary, then the Service's determination will not be changed.

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If I have an official CBRS determination letter from the Service that is a few years old, how can I tell if it is still valid?

If the Service's determination letter states that the property is located within the CBRS, the letter should list the CBRS unit number and date of the official CBRS map that was used to make the determination. To confirm whether the determination is still valid, the interested party can visit the Service's CBRS Mapper and follow these steps:

  • Locate the area of interest in the mapper.
  • Click on the location of interest. A pop-up window will open providing information for the area.
  • In the pop-up window, click on the map link. A PDF of the official map will then open in a separate tab or download.

If the date of the map on the website is the same as the date of the map referenced in the Service's letter, then the determination is still valid. If the determination letter states that the property is not located within the CBRS, there will be no unit number referenced in the letter, and therefore no way to check online to see if it is still valid. In cases such as this, the interested party should contact the Service office that issued the CBRA determination letter to see if a new map has been adopted that affects the subject property.

If the determination letter is no longer valid due to the adoption of a new map, the interested party should request a new CBRS determination from the Service.

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What is the process to change a CBRS boundary?

Please see the boundary modifications webpage on our website for information about how CBRS boundaries are changed.

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Can a CBRS boundary be changed via a Letter of Map Amendment?

No. CBRS boundaries cannot be changed by a Letter of Map Amendment. Aside from three minor exceptions, only Congress has the authority to modify boundaries of the CBRS through legislation. These exceptions include: (1) the CBRA five-year review requirement that solely considers changes in the units that have occurred due to natural forces such as erosion and accretion; (2) voluntary additions to the CBRS by property owners; and (3) additions of excess federal property.

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Can I make a voluntary addition of land to the CBRS?

Yes. The Service may administratively make additions to the CBRS if the owner of a parcel requests, in writing, that the Secretary of the Interior add the parcel to the System. The parcel must be an undeveloped coastal barrier in order to qualify for voluntary addition to the CBRS. For additional information, please contact the CBRA Program at

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How is the public informed of a CBRS mapping change?

Most changes to the CBRS require legislation to adopt revised maps. There are some minor exceptions (i.e., to address geomorphic change such as erosion and accretion, to allow voluntary addition of properties to the CBRS, and to add qualifying excess federal lands) where the Service can adopt revised maps through a notice published in the Federal Register. In either case, the Service publishes the revised maps on its CBRA website and updates the corresponding digital data in a timely manner (within days of the effective date, if not the same day) and sends a notification to its CBRA email listserv. Additionally, in recent years, the Service has sent notification letters directly to affected state and local officials to notify them of changes. The Service also publishes news releases and posts related information on the CBRA website in a table showing all historical changes to the CBRS.

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Are the CBRS boundaries available in digital format?

Yes. Geospatial CBRS boundary data is available in a variety of formats. These data are representations of the CBRS boundaries shown on the official CBRS maps referenced in 16 U.S.C. 3503(a). In general, these digital boundaries can be considered accurate to within approximately 20 feet of the actual CBRS boundaries shown on the official maps. Before using the data, please read the metadata for additional information.

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Where can I get more information?

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Whom do I contact when I have a question?

For general questions about CBRA, please email

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Aerial view of an undeveloped coastal freshwater pond.
We administer the Coastal Barrier Resources Act (CBRA), which encourages the conservation of storm-prone and dynamic coastal barriers by withdrawing the availability of federal funding and financial assistance within a designated set of units known as the Coastal Barrier Resources System (CBRS)....