(a) Real property shall not be deemed to be encumbered within the meaning of section 561 of this title by reason of the existence of:
(1) instruments reserving mineral, oil, timber or similar rights, rights of way, sewer rights, or rights in walls;
(2) liens for taxes or assessments not delinquent, or liens not delinquent for community recreational facilities, or for the maintenance of community facilities, or for service and maintenance of water rights;
(3) building restrictions or other restrictive covenants;
(4) encroachments, if such encroachments are taken into consideration in determining the fair value of the property;
(5) a lease under which rents or profits are reserved to the owner if in any event the security for the loan or investment is a first lien upon the real property; or
(6) with respect to loans secured by mortgage, deed of trust, or other collateral guaranteed or insured in full or in part by the Government of the United States, such encumbrances as are allowed as exceptions in title by the administrator or administration of the division of such government so guaranteeing or insuring.
(b) if under any of the exceptions set forth in subsection (a) of this section there is any sum owing but not due or delinquent, the total amount of such sum shall be deducted from the amount which otherwise might be loaned on the property. The value of any mineral, oil, timber or similar right reserved shall not be included in the fair value of the property.