Flood Map Modernization: Understanding the Effects of Map Changes

A Better Picture of Flood Hazards

Over time, water flow and drainage patterns can change dramatically due to surface erosion, land use and other forces.  The likelihood of flooding and flash flooding will change as well.  The older flood hazard maps in effect for Brazos County do not reflect these changes.  Initially created nearly 30 years ago, they are seriously out of date.  New maps using new digital mapping techniques, are now becoming available to provide detailed, reliable and current information on county and local community flood hazards.  The new flood hazard maps are also known as Digital Flood Insurance Rate Maps or DFIRMS.  They present a better picture of the areas likely to be affected by flooding and provide a stronger foundation from which to make building and land use decisions.

Newer Maps Mean Safer Communities

These maps are important tools in the effort to protect lives and property.  By showing the extent to which specific areas, neighborhoods and individual properties are at risk for flooding, flood maps help business and property owners make financial decisions about protecting their property.  They also enable community planners, local officials, engineers, builders and others to determine where and how new structures and developments should be built.

As the new maps are introduced, it is important that property owners, insurers, lenders, real estate agents and brokers, developers, and builders, understand what the changes are and what the effects will be.

Learn more about the effects and what you need to know:

Property Owners

Insurance Professionals

Lending/Realty Professionals




Property Owners

Flood Maps are Changing; Know Your Risk

Everyone has some level of flood risk.  New flood hazard maps provide an updated picture of what that risk is.  The level of flood risk can be different from neighborhood to neighborhood and even property to property.  Homeowners, renters and business owners will want to learn how their risk is currently shown, and how it will be shown when the new flood hazard maps (Digital Flood Insurance Rate Maps, or DFIRMs) become effective.


Insuring Against Changing Risks

When properties are mapped into high-risk areas (shown as flood zones labeled with letters starting with “A”), construction restrictions and flood insurance requirements may apply. In these areas, known as Special Flood Hazard Areas (SFHA), if a property owner has a mortgage through a federally regulated or insured lender, flood insurance will be required once the maps become effective. Some lenders may decide to institute such requirements before the date the maps become effective.  Property owners who obtain and maintain flood coverage before the effective date may be able to save through a process known as grandfathering.

Insurance agents can provide more information and explain the various flood insurance options.

When properties are mapped from high-risk areas into low- or moderate-risk areas (a zone labeled with the letter “X”),flood insurance may no longer be required once the maps become effective. However, the flood risk has only been reduced;it has not been removed.   Property owners can maintain coverage by converting to a lower-cost Preferred Risk Policy (PRP).  Again, insurance agents can explain the flood insurance options.


Flood Insurance Requirements and Options

When the new maps are adopted, flood insurance requirements will change. However, options exist that will allow property owners to save money while still protecting their property.

Change from low or moderate flood risk to high risk Flood insurance is mandatory. Flood insurance will be federally required for most mortgage holders.*  Insurance costs may rise to reflect the true (high) risk.Grandfathering offers savings.  The National Flood Insurance Program (NFIP) has “grandfathering” rules to recognize policyholders who have built in compliance with the flood map or who maintain continuous coverage. An insurance agent can provide more details on how to save.
Change from high flood risk to low or moderate risk Flood insurance is optional, but recommended. The risk has only been reduced, not removed.  Flood insurance can still be obtained, at lower rates. Twenty to twenty-five percent of all flood insurance claims come from low- to moderate-risk areas.Conversion offers savings.  An existing policy can be converted to a lower-cost Preferred Risk Policy.
No change in risk level No change in insurance rates.  Property owners should talk to their insurance agent to learn their specific risk and take steps to protect their property and assets.

* Required for loans provided by federally regulated and insured lenders as well as Government Sponsored Enterprises such as Freddie Mac and Fannie Mae.


Flood Risks and Flood Zones

Flood maps refer to areas of high, medium or low risk as “flood hazard zones” and the zones of highest risk as “Special Flood Hazard Areas.”

High Flood Risk AE, A, AH or AO Zone.  These properties have a 1 percent chance of flooding in any year — and a 26 percent chance of flooding over the life of a 30-year mortgage.Insurance note: High-risk areas are called Special Flood Hazard Areas, and flood insurance is mandatory for most mortgage holders.*
Low or Moderate Flood Risk Shaded X Zone.  These properties are outside the high-risk zones.  The risk is reduced but not removed.X Zone.  These properties are in an area of overall lower risk.Insurance note:  Lower-cost preferred rate flood insurance policies (known as Preferred Risk Policies) are often an option in these areas.

* Required for loans provided by federally regulated and insured lenders as well as Government Sponsored Enterprises such as Freddie Mac and Fannie Mae.



Insurance Professionals

Flood Maps are Changing; Know Your Options

Updated digital flood hazard maps, DFIRMs, may bring changes in flood insurance requirements for property owners.  It is important for insurance professionals to learn how their clients will be affected by the new maps and what the best options are.


Mapped to a Higher Risk: The Grandfathering Option

When properties are mapped into a high-risk area, flood insurance will be required for most mortgage holders.  Before new the newDFIRMs go into effect, insurance agents and brokers should compare the two sets of maps (the current effective map and the new preliminary map) to see if any clients will be affected and should therefore be alerted to the upcoming change.  If a building is going to be mapped into a high-risk zone or if the Base Flood Elevation (BFE) is increasing, encourage the owner to purchase (or maintain) a policy now.  That way the owner is protected now, and can “grandfather” or lock in that zone or elevation to maintain eligibility for the corresponding insurance rate when the map changes.  For homes built before the community’s first flood map was issued (known as Pre-FIRM buildings), purchasing a flood policy before the new maps become effective is the only way to lock using rates associated with the earlier zone.  Note, however, that sometimes the new maps may actually provide for a better premium than through grandfathering.  For more details, refer to FEMA’s NFIP Map & Zone Grandfather Rules and Page 22-24 of the National Flood Insurance Program’s Producer Manual.


Mapped to a Low – Moderate Risk: Convert to a PRP

If properties are being mapped out of a high-risk area, the policies may be eligible for conversion to Preferred Risk Policies (PRP) when the new map becomes effective.  The owner will receive a refund for the difference in the premium paid between the standard rated policy in the high-risk zone and the new PRP, while remaining covered.  More information on conversion can be found on theNFIP Conversion Fact Sheet.

Insurance agents and brokers should remember that they must always rate flood insurance policies using information from the Flood Insurance Rate Map currently in effect….not from the preliminary flood map.


New Vertical Datum

As part of the nationwide Map Modernization effort, the new DFIRMs are using a new vertical datum as the base for all elevations (NAVD88).  This datum is a much more accurate one than the almost 80-year old one used for the previous flood maps (NGVD29). As a result, a building’s base flood elevation could show one measurement on the old map (i.e., 75’) and another measurement on the new map (i.e., 78’) though its actual elevation will not have changed.  So, before grandfathering a property where elevation is involved, make sure that the elevation on the elevation certificate and the BFE on the FIRM are both using the same vertical datum.



Lending/Realty Professionals

Changing Maps, Changing Risks

As the new flood maps are released, they will reflect current flood risks, replacing maps that are almost 30 years out-of-date.  As a result, lenders and real estate professionals will have reliable, Internet-accessible information about flood risk on a property-by-property basis.  As preliminary maps are released and the date approaches for maps to become effective, many property owners will learn that their flood risk is higher, or lower, than they thought.  The changes may affect closings and existing loans for both residents and business owners throughout the area.


Lenders Can Avoid Closing Delays

If a building is shown to be in a high-risk zone on the flood map currently in effect, flood insurance must be in place if there is a mortgage through a federally regulated lender.  This requirement does not change when new preliminary flood maps are released. Lenders (or their flood zone determination company, if they outsource that service) cannot use preliminary flood maps to determine federal insurance requirements.  (However, some lenders may decide to require flood insurance as part of their own internal underwriting of the loan.)

As the date that the maps become effective gets closer, loan originators and mortgage brokers will want to refer to the preliminary maps to determine whether a property might be mapped into a high-risk area when the maps do become effective.  By informing the borrower of this potential change before a loan is finalized, they will help minimize any delay in loan closing due to changes in flood zones and flood insurance requirements.

Once the new flood maps become effective, federally regulated lenders will notify property owners that have been mapped into a high-risk area that they are now required to carry flood insurance.  Property owners that have been mapped out of the high-risk areas will be informed that they no longer are required to carry flood insurance.  However, removing the requirement does not guarantee that it will not flood; property owners should be encouraged to stay protected with a lower-cost Preferred Risk Policy.


Real Estate Professionals Can Avoid Unpleasant Surprises

Real estate professionals can also use the preliminary flood maps to determine how proposed zone changes are likely to affect any properties that are for sale.  This will help avoid any surprises at the time of closing that could delay and perhaps jeopardize the purchase/sale of a property.  Real estate agents and brokers should also become familiar with the flood insurance grandfather options that can help keep their clients’ insurance costs down, including the possible transferring of a seller’s existing flood insurance policy to the new owner.



Builders / Developers / Engineers

New Flood Maps: Building to a Safer Standard

Flood hazard maps can be valuable tools in the effort to protect lives and properties.   The County’s current flood maps are nearly 20 years out–of-date. The new flood maps provide a much more accurate picture of flood risks and flood elevations to guide in land development and building decisions.


Engineers/Developers/Builders Can Plan for Safer Construction

When preliminary flood maps are released, the building industry will need to know the differences between the preliminary maps and the current effective map.  The data from the more conservative map is typically used by communities for design and permitting purposes.  This will remain the case until the preliminary maps become effective.  When the preliminary map shows less restrictive information, it usually cannot be used until that map becomes effective.


The Vertical Datum is Changing

As new flood maps are issued, they will no longer be using the National Geodetic Vertical Datum of 1929 (NGVD29) as the vertical datum (see the Federal Emergency Management Agency’s Procedure Memorandum 41).  Instead, they will use the North American Vertical Datum of 1988 (NAVD88).  Floodplain managers, surveyors, engineers, builders, and other users of elevation data from multiple sources (e.g., a FIRM and elevation certificate) must take care that the elevation values they use are based on the same vertical datum. If they are not the same, the values need to be converted to the same datum. Failure to do so can result in improper design (e.g., building at the wrong elevation).  Note that the property owners’ risk is not affected by a vertical datum change because all elevations in the local area are changed by the same amount.