United States: Flood Zone Designations

Last Updated: December 19 2001
Article by C Edward Kuntz

Many people may not know whether, or to what degree, their communities are subject to flooding. The Federal Emergency Management Agency, through its National Flood Insurance Program, compiles and disseminates information on the flood hazard potentials of communities across the nation. Thousands of communities have been studied, mapped and assigned flood zone designations based on their propensity for flooding. This information is not only of great interest to individual property owners but also to real estate investors and lenders.

Flooding is one of the leading causes of property damage in the United States. In response to escalating annual losses from flooding, Congress enacted the National Flood Insurance Act of 1968 which created the National Flood Insurance Program (NFIP). The NFIP is administered by the Federal Emergency Management Agency (FEMA) and its subsidiary agencies. This federal program enables property owners in participating communities to purchase flood insurance. Participation in the NFIP is based on voluntary agreements between individual communities and the government. To date, more than 18,000 communities with significant flooding potential have elected to join the program. If a community agrees to implement floodplain management measures designed to mitigate flood risks in hazardous areas, the federal government will make flood insurance coverage available to owners of insurable property within that community. Moreover, the Flood Disaster Protection Act of 1973 and the National Flood Insurance Reform Act of 1994 require the purchase of flood insurance as a condition of receiving federally related financial assistance for most acquisition and construction purposes in areas identified by FEMA as having special flooding hazards.

As a result, it is important for individual property owners, as well as real estate investors and lenders, to determine whether property is located in a community participating in the NFIP and the flood zone designations, if any, of the property.

FEMA conducts studies throughout the country to determine the location of flood hazard areas. A Flood Insurance Study (FIS) involves in-depth analyses of a community's hydrologic and hydraulic data, river-flow, precipitation, tidal surge, wind velocity, land development, topography and other available scientific data. In addition, FEMA organizes local public meetings for purposes of gathering all relevant information needed to ensure accurate study results.

In conjunction with these studies, FEMA produces flood maps identifying a community's flood hazard areas and the levels of risk associated with each area. Communities are provided copies of their flood maps, which commonly are placed on file in local planning, zoning, or engineering offices. Members of the public may review these maps to learn the flooding designation(s) of a particular parcel of land. Flood zone maps routinely require revisions due to changing weather patterns, land development and other variable factors. In this regard, property owners who believe existing flood zone maps are inaccurate may take a proactive approach by engaging a civil engineer to produce flood elevation certificates or other evidence to show that their property is outside the 100-year floodplain. However, the process may be time consuming and expensive and the burden will be on the property owner to persuade FEMA that the existing flood zone map is inaccurate.

The most widely distributed flood map issued by FEMA is the Flood Insurance Rate Map (FIRM). Several areas of flood hazard are displayed on the FIRM. One of these areas is the Special Flood Hazard Area (SFHA). The SFHA is a high-risk flood area, commonly termed the 100-year floodplain. This term, however, often is misconstrued. Contrary to popular belief, it does not mean that during a 100-year period, there is a 100-percent chance that flooding will occur. Nor does it mean that if flooding does occur, it will not reoccur for another 100 years. Rather, the SFHA or 100-year floodplain is an area having a one-percent or greater chance of flood occurrence in any given year. This means that over a 100-year period, there is a 63.5-percent chance of flooding in a SFHA. According to FEMA, a structure located in a SFHA has a one-in-four chance of sustaining flood damage during the term of a 30-year mortgage. As a result, flood insurance is a prerequisite for obtaining federally insured loans for structures situated in SFHAs.

SFHAs are subdivided into zones beginning with either the letter V or A. V-lettered zones are coastal hazard areas, such as beach-front properties, where flooding risks are heightened due to wave velocity. V designations traditionally have been accompanied by a number (V1-V30) indicating base flood elevations. For the sake of simplicity, however, new and revised FIRMs are replacing all numbered V zones with the designation VE.

VO zones are coastal areas of shallower water depths ranging between one and three feet.

Property located in A-lettered zones is subject to flooding from rising water and may be located near lakes, rivers or streams. These zones also have been coupled in the past with a number (A1-A30) indicating base flood elevations. They, too, are being redesignated simply as zone AE on new and updated maps.

Zone A may be further divided into zones AH, AO, A99 and AR. Zone AH represents areas of ponding subject to shallow flooding. Zone AO also encompasses areas of shallow flooding typically due to sheet flow on sloping terrain. A99 zones are special hazard flood areas where local flood control programs have been partially completed. The AR prefix signifies that a community's once accredited flood protection system has been discredited but is in the process of being restored to provide base flood protection.

In addition to the SFHA, areas of moderate and minimal flood risk are depicted on the FIRM. Property in these lower-risk areas may be vulnerable to flooding as a result of severe, concentrated storm activity combined with inadequate local drainage. Moderate flood risk areas are designated as B zones, and minimal risk areas are classified as C zones. New and revised maps redesignate both zones with the letter X. NFIP insurance coverage is available in these lower risk areas.

Zone D is the FIRM designation for areas where flooding hazards have not been studied but where flooding is nevertheless possible. Typically, these areas are not heavily populated. The mandatory flood insurance requirements generally are not imposed in D zones but coverage may be available.

The FIRM designations discussed above have become a customary disclosure item on the list of survey requirements required by institutional, conduit, and federally insured lenders. The wary real estate professional will have this information in hand well before getting the unwelcome news regarding mandatory flood insurance.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

In association with
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


From time to time Mondaq may send you emails promoting Mondaq services including new services. You may opt out of receiving such emails by clicking below.

*** If you do not wish to receive any future announcements of services offered by Mondaq you may opt out by clicking here .


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.