Flood plain surveys involve locating the position of the line of flood plain as delineated by the FEMA maps. This delineation is important for the insurance companies to know where you stand in relationship with the 100-year flood plain.
The surveyor usually provides a map of his findings in the field and how the flood plain impacts your property. Insurance companies will determine if you will need to acquire flood insurance for your property based in this information. It may be that they determine that your property is in such a position that they will not give you flood plain insurance.