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Why Are So Many Structures’ Flood Zones Incorrectly Rated?

Homeowners are frequently baffled when they learn their property’s flood zone, or FEMA updates their area’s floodplain map. Their home is within a high-risk flood area, but when they look around they don’t understand why.

Approximately 60% of structures are incorrectly rated in FEMA’s flood zone maps. This can cost homeowners thousands of dollars and unnecessary stress. But why are so many structures incorrectly rated?

Outdated flood maps, mismatched elevation data, incongruencies on maps regarding the location of bodies of water, and averaging elevation per city instead of looking at each structure individually, are some of the major factors for incorrect flood zone ratings.

Sometimes floodplain maps are updated based on elevation data collected in the 1970’s and 80s, which causes issues because: 1. Things change, and 2. They don’t consider recent flood data.

Most of the times though, FEMA and the local municipalities do a good job of establishing high-risk flood zones. The problem and errors occur because by necessity they look at everything from a macro scale. The big picture, if you will. It is impossible for them to create models that are accurate on a property-by-property basis. They don’t have the resources for that. So they look at entire cities at a time, not structure by structure. For example, if an average elevation in an area is 8 feet, you might have some structures at 6 feet and some at 10.  

There is new technology to gather more accurate elevation data than in previous decades. Lidar, which uses airplanes to map terrain by firing laser pulses at the ground, can provide data that is 10 times more accurate than the old methods. But it’s expensive, and we know what’s happened to FEMA’s funding in the last few years… As a floodplain mapping coordinator from Maine notes, they don’t have enough funding to update every map using this new technology.

Another reason for structures being incorrectly rated is not taking into account building code updates. Building codes change over the years, updating practices to protect homes from floods. Since the 1980’s, new construction has been required to build to make flooding unlikely. So basically, any structure built in the last 40 years is most likely built above or outside the impact of a flood event that has occurred in the last 100 years.

These are only a few of the reasons why we recommend getting a flood zone audit. Homeowners should not be burdened paying high flood insurance premiums and be worried that their homes might flood when, in fact, the risk is smaller than an incorrect flood zone classifications leads them to believe.

Contact us today for a free assessment by our Certified Experts to determine if your property can be removed from the FEMA Flood Zone.

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