39 C.F.R. § 776.7
Lease, easement, right-of-way, or disposal of property to non-federal parties
When postal property in floodplains is proposed for lease, easement, right-of-way, or disposal to non-federal public or private parties, the Postal Service shall:
(a) Reference in the conveyance document that the parcel is located in a floodplain and may be restricted in use pursuant to federal, state, or local floodplain regulations; or
(b) Withhold the property from conveyance.