Answer:
From page 30 of the Mandatory Purchase of Flood Insurance Guidelines book:
The regulations require the lender to retain a record or evidence of the borrower's receipt of the notice throughout the period the lender owns the loan. This record can be the borrower's statement or initials that the notice was received directly, or the U.S. Postal Service return receipt in either hard copy or electronic format. The lender need not retain a hard copy version of the notice to the borrower and loan servicer.
First published on BankersOnline.com 7/30/07