How is the Flood Zone Code determined?

There is a Flood Zone Code that displays when you go to Additional Info> Flood Map that shows the flood zone(s) a parcel is in.

There are many instances, however, where a single parcel is located within multiple flood zones:

If any part of the parcel is within a flood zone, that is the zone with which the parcel is associated. In the above example, the parcel is actually within several different zones. Since part of the parcel is located in the 100 year zone, that is what displays in the Flood Zone Code field.

The MLS has nothing to do with flood zone determinations- those are done by FEMA.