Depending on which state you are considering, elevation may not be what you think. 

 

Textbook, scientific and engineering definitions may or may not help.  For example Base Flood Elevation (BFE) is the expected height of floodwaters or the water surface elevation of the base flood rounded to the nearest foot.  And?  On an architectural floor plan or site survey, there are typically notations with the letters EL (elevation) followed by a number.  The number following the EL is often a measurement in feet.  So an EL followed by a 21 would indicate an elevation of 21 feet.

 

Some may think: “the higher the elevation number, the better”, right?  After all, doesn’t elevation involve the distance or measurement above sea level (ASL) or above mean sea level (AMSL)?   

 

Well, for the most part yes but what’s key is that there are actually two elevations involved.  The first is the BFE and the other is the FFE (first or finished floor elevation).  If the BFE is 19’ and the FFE is 21’ the elevation of the home or building’s lowest finished floor is 2’ higher than the estimated height floodwaters are projected to reach.

 

If the FFE of a home is 173’ and the associated BFE is 171’ the home is situated 2’ higher than the height of anticipated flooding. 

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So whether the elevation of a home’s lowest finished floor is 21’ or 173’, it may be good to find out if the property is located in a floodplain or not?  A floodplain is identified as any land area susceptible to being inundated by water. 

 

The Federal Emergency Management Agency (FEMA) has flood zone designations, maps, and websites containing tools to inform home buyers about flood risk.  The various zones are as follows:

 

Undetermined Risk – Zone D

Low Risk – Zones C and X (unshaded)

Moderate Risk – Zones B and X (shaded)

High Risk – Zones A, AE, A1-30, AH, AO, A99

Coastal High Risk – Zones V, VE, V1-30

 

In addition to FEMA’s assessment, flood risk data is also made available by private and non-profit organizations.

 

So, what about a lakefront home that has a basement or lower floor?  The site survey might reflect something like: a Lower Floor Foundation Elevation (LFFE) of 104’ with an Upper Floor Foundation Elevation (UFFE) or FFE of 116’.  The property may have an attached garage with a garage elevation (GE) of 113’.  But what about the BFE?  Although the lake is flood zone AE the home itself may be listed as flood zone X where no elevation certificate (EC) is required.  The site survey may also include a notation near the rear of the property labeled Normal High Water Line Elevation (or NHWE).  The NHWE measurement is also in feet and for this lakefront property example, the NHWE is 99’.  Since the elevation of the lowest finished floor is 104’ the home is currently above NHWE, which is a good thing. 

 

After doing some digging (figuratively speaking), it is discovered that the home’s subdivision has a Master Grading & Drainage Plan done by a licensed civil engineering, planning and architectural firm.  The Master Grading & Drainage Plan includes a notation labeled 100YR ELEV 102’.  So likely, there was a detailed analysis and comprehensive study done.  Nice.

 

On most flood maps there are notations such as AE EL 8 or VE EL 10.  Often, the AE or VE will indicate the FEMA flood zone and the EL (elevation) will denote the base flood elevation requirement.

 

Depending on your location, there is likely a local floodplain manager.  If the home you are considering is located in a high-risk flood zone area there may even be an EC on file for that property.  Most communities participating in the National Flood Insurance Program (NFIP) will usually have a floodplain manager, storm water manager or other key contact personnel perhaps in planning & zoning.   

 

So what’s the difference between a floodplain and a flood zone?  A floodplain is a geographic area adjacent to a river or stream that is prone to flooding, while a flood zone is a designated area on a map indicating the likelihood of flooding based on risk assessments.  Floodplains are naturally occurring areas that are periodically inundated with water during periods of high discharge.  These areas are characterized by flat terrain and fertile soil due to the accumulation of sediment deposited by the river (or relevant body of water) over time.

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The state of Florida has a Flood Disclosure form (i.e., in addition to the seller’s property disclosure form) that Florida Statute 689.302 requires. However, the Flood Disclosure seems to focus more on insurance claims and FEMA payments rather than the question of whether or not water was in the home? If we wanted to know if a car was ever in an accident, we might do better asking "if the car was ever in an accident" rather than asking if an automobile insurance claim was ever filed.  Similarly, If a homeowner self-insures there could have been water in the home with no insurance claim(s) filed. So, you might want to plainly ask: “has there ever been water (i.e., flooding) in the home?”