Rev. & Tax. Code, § 20808

(a) (1) “Residential dwelling” means a dwelling, and the land surrounding that dwelling as is reasonably necessary for the use of the dwelling as a home, occupied by the claimant as his or her principal place of residence, and owned by any of the following:

(A) The claimant.

(B) The claimant and the claimant’s spouse.

(C) The claimant and his or her parents, children (whether natural or adopted), or grandchildren of either the claimant or the claimant’s spouse.

(D) The claimant and the spouse of any parent, child (whether natural or adopted), or grandchild of either the claimant or the claimant’s spouse.

(E) The claimant and another individual who resides in this state and is eligible for deferment under this chapter.

(2) “Residential dwelling” shall also include all of the following:

(A) A condominium that is assessed as real property for local property tax purposes.

(B) A portion of a multidwelling or multipurpose building and the portion of land upon which it is built.

(C) A mobilehome that is permanently attached to a permanent foundation and assessed as real property for local property tax purposes.

(b) “Residential dwelling” shall not include any of the following:

(1) Any dwelling in which the claimant does not have an equity value of 20 percent, as described in paragraph (3) of subdivision (a) of Section 20802.

(2) Any dwelling in which the claimant’s interest is a life estate or is held pursuant to a contract of sale, unless the claimant obtains the written consent of the holder of the reversionary interest subject to the life estate, or the vendor under the contract of sale, for the claimant to participate in the program with respect to the dwelling.

(3) Any dwelling for which the claimant does not receive a secured tax bill.

(4) Any dwelling in which the claimant’s interest is held as a possessory interest, except a life estate as described in paragraph (2).

(5) Any houseboat or floating home.