Elevation certificates can be confusing and if not entered correctly it could cost you thousands of dollars each year. So its important to understand exactly what the different elevations on the elevation certificate mean and how it can impact your flood insurance rates?

First  let's talk about the base flood elevation, what is a base flood elevation?
According to FEMA Base flood elevation or BFE is the computed elevation to which floodwater is anticipated to rise during the base flood. So let's imagine the BFE is the water level in the ocean, if your house is above it then you might be in a boat but if your house is below it you might be under water.

Each one of the elevations we are going to discuss is going to be compared to the BFE in determining the flood insurance rate through FEMA. When reviewing the elevation certificate the numbers you will generally be looking for will be in Section C2. 

The first elevation is going to be top of the bottom floor. This is generally going to be the lowest level of the foundation like a crawlspace, basement or slab. Depending on the foundation type if this level is below the BFE it could have a significant impact on the rate. For example subgrade foundations with a negative elevation level will have a bigger impact on rates than above grade foundations will.

The next elevation to review will be C2 section B which is the top of the next highest floor. In many situations this will be the first rated floor. For example if you have an above grade crawlspace and you have flood vents then you maybe able to count this as the lowest rated floor. This could cause a drastic decrease in flood insurance premiums.

The next section is C2  section d which is an attached garage depending if the garage contains equipment like a water heater or furnace it could have little impact on the flood insurance rate.

The next section of the elevation certificate is section C2 part E this part can be crucial to flood insurance rates. This is the lowest level of machinery equipment. This is talking about things like air conditioners and furnaces. Lets say the rest of the house is above the BFE which gives you possibly preferred rates but the servicing equipment is not then you get stuck with high risk rates. This is one reason why people elevate this equipment to make sure it is level with the lowest floor. This way the equipment does not have a negative impact on your flood insurance rates. This has become a common practice in low lying areas like Houston Texas, Findlay Ohio, Des Moines Iowa, and Montgomery Alabama.

The next section is part F this is the lowest adjacent grade of the building. This means the elevation of the ground, sidewalk or patio slab immediately next to the building, or deck support, after completion of the building. The lowest point of the ground level immediately next to a building.  The importance of this level is can determine if your property qualifies for a letter of map amendment which could remove it from a high risk flood zone. One of FEMA's conditions is that the lowest adjacent grade or LAG be above the base flood elevation. One reason is if it is below you can imagine what flash flooding could do to the property.

One the last sections is part G the highest adjacent grade also known as HAG. HAG is the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.

The last part of section C2 is h this has to do with the lowest adjacent grade of things like a deck or structural support of a property. When it comes to flood insurance rates things that have the biggest impact on rates are living areas. So areas used for parking or access like a garage or deck may not impact things as much.

As you can see all these different numbers can be confusing like what number is the most important? Just remember the lower the home is below the base flood elevation the higher the rate is. If you need help with understanding an elevation certificate reach out to a local flood insurance expert like The Flood Insurance Guru or a surveyor.

Chris Greene


Chris Greene

President of The Flood Insurance Guru
M.S. in Emergency Management with a focus in Flood Mitigation