California Code, Revenue and Taxation Code - RTC § 5803

(a) “Full cash value” means the “full cash value” or the “fair market value,” as determined pursuant to Section 110, of a manufactured home similarly equipped and installed, including any value attributable to a manufactured home accessory building or structure as defined in Section 18008.5 of the Health and Safety Code which is sold along with the manufactured home, giving recognition, however, to the exemption provided in subdivision (m) of Section 3 of Article XIII of the Constitution.

(b) The Legislature finds and declares that, because owners of manufactured homes subject to property taxation on rented or leased land do not own the land on which the manufactured home is located and are subject to having the manufactured home removed upon termination of tenancy, “full cash value” for purposes of subdivision (a) does not include any value attributable to the particular site where the manufactured home is located on rented or leased land which would make the sale price of the manufactured home at that location different from its price at some other location on rented or leased land. In determining the “full cash value” of a manufactured home on rented or leased land, the assessor shall take into consideration, among other relevant factors, cost data issued pursuant to Section 401.5 or sales prices listed in recognized value guides for manufactured homes, including, but not limited to, the National Automobile Dealers Association's Manufactured Housing Appraisal Guide.