What Is Flood Zone X?

The Federal Emergency Management Agency (FEMA) has identified several flood hazard areas, i.e., areas at risk of flooding. Among them is Flood Zone X. What defines Flood Zone X, and how severe is the risk of flooding in this flood zone?

Flood Zone X is an area identified as having either a moderate or low risk of flooding. However, it is an area where you should still be prepared for potential flooding.

Learn more about what FEMA has classified as Flood Zone X and how living in this flood zone matters.

fema difined flood zones

What is Flood Zone X?

FEMA identifies Special Flood Hazard Areas (SFHA’s) as areas likely to be inundated by a flood event with “a 1-percent chance of being equaled or exceeded in any given year” [1] based on a 100-year flood record. They are shown on a Flood Insurance Rate Map (FIRM) and are defined by a Base Flood Elevation (BFE). Here, we elaborate on the two areas designated as Flood Zone X:

  • Flood Zone X shaded, also called Flood Zone B, is a moderate flood hazard area where the annual risk of flooding is between 0.2% and 1%. It lies between the limits specified by the base flood elevation and those having a 0.2% annual chance of a flood (based on a 500-year flood record).
  • Flood Zone X unshaded, also called Flood Zone C, is a minimal flood hazard area where the annual risk of flooding is less than 0.2%. It lies outside an SFHA due to having a higher elevation than Flood Zone B.

flood zones

Base Flood Elevation

Based on previous flood records, Base Flood Elevation (BFE) defines the height that a flood is most likely to reach. It assumes the flood water level will not go higher than the BFE. The BFEs are not specified for Flood Zone X because it lies outside an SFHA, an area at risk of inundation by a flood.

Risk of Flooding in Flood Zone X

Although Flood Zone X lies outside an SFHA, it only means the annual risk of flooding is lower than 1%, i.e., it has less than a 1 in 100 chance of a flood occurring based on the previous 100-year records. It does not mean the area is not prone to flooding or that it will never flood. It means Flood Zone X is a moderate-to-low flood risk area, with not as high a risk as other areas that come under SFHA. Areas under Flood Zone X are still marked on a FIRM, despite lying outside the SFHA.

Another critical thing to understand is that the flood risk in any zone is determined based on historical data. The moderate or low risk in Zone X is an expression of the likelihood of flooding after taking past high water levels into account. Also, the actual risk of flooding in your particular spot in Zone X will depend on how high or low your dwelling is compared to the surrounding area.

Flood maps can and do change over time as well. If you’ve been living in Flood Zone X shaded (or B), the area could be reclassified as Flood Zone X unshaded (or C) if it does not flood there for 100 years. Likewise, a Flood Zone X unshaded (or C) designated area may be reclassified sometime later to Flood Zone X shaded, or another flood risk zone or no flood risk zone can also be reclassified.

Does Living in Flood Zone X Matter?

Besides worrying about the potential damage caused by flooding, if you live in or near a Flood Zone X area, knowing that you do matters for several more reasons:

  • Flood risk – The risk is still present because the flood risk is low to moderate. Read the section above on ‘Risk of Flooding in Flood Zone X.’
  • Flood preparation – Because flood risk is still present, you should be prepared for the eventuality.
  • Flood insurance – Although Flood Zone X is outside an SFHA, it could make a difference to your home insurance.
  • Elevation certificate – If you don’t live in Flood Zone X but live very close to one, you could potentially still be at risk, and your insurance provider may require an elevation certificate.

Useful Links

To know which flood zone your area is in, enter your location or coordinates on FEMA’s Flood Map Service Center website.

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[1] FEMA. Flood zones. Retrieved from https://www.fema.gov/glossary/flood-zones. 2020.

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