Cal. Rev. & Tax. Code § 2188.4
Whenever a portion of a parcel of land, other than that used for grazing or other agricultural purposes and property assessed by the State Board of Equalization, is subject to a lease which is recorded or for which a memorandum of lease is recorded and which provides for a term (including options to renew) of 15 years or more from the commencement date of the lease and which requires the lessee to pay, or to reimburse the lessor for, the property taxes (or any portion thereof) on the leased premises, the assessor shall separately assess the land and improvements subject to the lease and the land and improvements not subject to the lease upon application for such separate assessments by the lessor or lessee prior to the lien date; provided the boundaries of the leased area do not pass through any improvement except along a bearing partition; and provided that each parcel as described must have access frontage on a dedicated street. The assessor shall thereafter continue to make such separate assessments until the expiration date of the lease or at an earlier date should the lessor or lessee file a written request that the separate assessments be discontinued.
The assessor may, in his discretion, assess the leased premises to the lessor or the lessee; provided, that if the lessor is assessed, all notices of assessment and tax bills relating to the leased premises shall be mailed to the lessor in care of the lessee at the lessee's latest address known to the assessor, or a copy of such notices and bills shall be mailed to the lessee at such address.
Ca. Rev. and Tax. Code § 2188.4