Whenever improvements are owned by a person other than the owner of the land on which they are located, the owner of the improvements or the owner of the land may file with the assessor a written statement before the lien date attesting to their separate ownership, in which event the land and improvements shall not be assessed to the same assessee.
Such written statement shall not be required annually following the year in which it has been filed but shall remain in effect until such time as either, or both, of said separate ownerships shall have been transferred or until such written statement of separate ownership shall have been canceled by either the owner of the land or the owner of the improvements.
Source:
Section 2188.2, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC§ionNum=2188.2..