If you are not taking a lien on any of the mobile homes and there are no other walled,roofed structures on the land you are taking as collateral, then FDPA rules would not apply to your loan. If there is a walled,roofed structure on the land, then you would need to require flood insurance if the building sits in the portion of the land that is in a SFHA. With some additional information provided to them, your vendor should be able to advise whether or not the building sits in the SFHA. If the mobile homes are not permanently affixed to the land, then the FDPA rules would not apply even if you were taking a lien on them.