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Indiana Floodplain Mapping FAQs

Frequently Asked Questions

Q. What is a Base Flood Elevation (BFE)?

A. A Base Flood Elevation (BFE) is the elevation the floodwaters will reach during the 1 percent annual chance flood.

Q. What is the 1 % Annual Chance Flood?

A. The 1 percent annual chance flood (also known as the 100-Year Frequency Flood or Base Flood) is the flood that has a 1 percent chance of being equaled or exceeded in any given year. Any flood zone that begins with the letter A is subject to the 1 percent annual chance flood.

Q. I have flood insurance and my house is in an A Zone according to the current flood map. The new flood map, however, will show my house as being in a low-risk flood zone (B, C, or X-zone). Will I have to continue to carry flood insurance when the new map takes effect?

A. If you have Federal or federally related financing for your home, you will no longer have a Federal requirement to purchase flood insurance when the new flood map takes effect. However, lenders still have the right to require flood insurance, even for buildings no longer in an A Zone. If you want to continue coverage after the new maps take effect, you may be eligible for much lower rates based on your home being outside the A Zone. You should have your policy re-rated using the new maps, which should lower your premium. Even if you are not required to purchase flood insurance, homeowners are encouraged to continue coverage at the lower rates in the event you are flooded by an event greater than the 1% annual chance flood.

Q. My house is not in an A Zone according to the current flood map, but the new map will show it as being an A Zone. Will I have to purchase flood insurance when the new map officially takes effect?

A. Yes, if you have Federal or federally related financing for your home and you do not already have flood insurance. Your lender will contact you once the new map takes effect and require you to purchase flood insurance. If you do not purchase the insurance within 45 days after being notified, the lender can purchase the insurance for you at a higher premium and charge you for the cost. If you dispute the determination that your home is located in an A Zone, you and your lender can jointly request a Letter of Determination Review from FEMA at a cost of $80. The review request must be submitted within 45 days of notification that your home is located in an A Zone. If you have insurance before the new maps take effect, the basis for rating that policy is unchanged.

Q. How does a preliminary map become effective?

A. After the open house, there is a 90-day appeal period to challenge the preliminary mapping. Updated maps become final six months after all disputes have been resolved.

Q. What if a person disagrees with the new flood zone for a piece of property?

A. There are two options:

  • Appeal Process
    The appeal is a formal objection to new or revised Base Flood Elevations (BFEs) shown on a Preliminary Digital Flood Insurance Rate Map (DFIRM) or Flood Insurance Study (FIS) report. Predicted flood elevations can be appealed if they are shown to be scientifically or technically incorrect. The distinction between "scientifically incorrect" and "technically incorrect" is important because of the differences in the types and amounts of data needed in support of an Appeal Petition.

    A study that determines BFEs along a stream involves collection of historical and physical data, followed by analyses to determine flow rates and water-surface elevations. Various information is required to support an appeal, depending on the part of the study being challenged.

  • Protest Process
    A formal objection to any new or revised information shown on a Preliminary DFIRM or FIS report submitted during the 90-day appeal period that does not involve BFEs is considered a protest. Protests generally involve comments regarding the delineation of the updated floodplain and/or floodway boundaries, corporate limits, road names, and road locations.
  • Resolution of Appeal and Protest Petitions
    The Indiana DNR will send an Acknowledgement Letter notifying the community that an Appeal or Protest has been received. The supporting data will be reviewed to determine if it constitutes a valid Appeal or Protest and if the formal petition supports a revision. After reviewing all submitted data, an Appeal Resolution Letter will be sent to the community explaining the resolution of the Appeal or Protest. A revised Preliminary Transmittal Letter, including a revised Preliminary FIS report and/or DFIRM that incorporates changes made, as a result of the Appeal or Protest, will be sent to the community, if necessary. The community has 30 days to review and comment on the resolution when necessary. At the end of the comment period and after all resolutions are completed, FEMA issues a Letter of Final Determination to the impacted community, publishes the new or revised BFEs in the Federal Register, and initiates the final production of the FIS report and DFIRM.

Q. How can I find out when new maps will become available for my community? How can I get more information?

A. Visit the Indiana Department of Natural Resources, Division of Water's website at:

Or contact us at:

Indiana Department of Natural Resources
Division of Water
402 W. Washington Street, Room W264
Indianapolis, IN 46204
877-928-3755 (Toll Free)


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