36 C.F.R. § 73.13
(a) Requirements.
(b) Protection Measures for Public Properties. For properties owned or controlled by Federal, State, and/or local governments, the following items satisfy the protection requirements outlined in paragraph (a) of this section:
(2) The nomination document must include reference to:
(c) Protection Measures for Private Properties. For properties owned or controlled by private organizations or individuals, the following items satisfy the protection requirements outlined in (a) of this section.
(2) The opinion of counsel on the legal status and enforcement of such a prohibition, including, but not limited to, enforceability by the Federal government or by interested third parties.
In addition, if the owner(s) is willing, a right of first refusal may be given for acquisition of the property, along with a guaranteed source of funding and appropriate management framework, in the event of any proposed sale, succession, voluntary or involuntary transfer, or in the unlikely event that the requirements outlined above prove to be inadequate to ensure the preservation of the property's outstanding universal value. The protection measures for each private property being considered for possible nomination to the World Heritage List will be reviewed on a case-by-case basis to ensure that the requirements set forth above fulfill the mandate of Pub. L. 96-515.