Here's a section from page 25 of the
Mandatory Purchase of Flood Insurance Guidelines .
(4) No Coverage if Land Loan Only
If a lender makes a loan in which there is no lien on any land upon which there is a building, i.e., improved real property, the flood insurance purchase requirement does not apply. The NFIP does not insure land, and the 1994 Reform Act does not address mortgages secured by land alone. Similarly, if the purpose of a loan transaction is to facilitate the purchase of land for subsequent development, and any improvement on the real property is of nominal value,
the wording of the mortgage must specifically exclude the building as part of the security for the loan in order to avoid the mandatory purchase requirement. This is consistent with the purposes for which the purchase requirements of the 1994 Reform Act were adopted: to protect lenders and Federal resources against potential losses resulting from uninsured secured loans, and to protect unwary borrowers against financial losses resulting from losses to uninsured buildings.