California Code, Revenue and Taxation Code - RTC § 5801

(1) Was first sold new on or after July 1, 1980.

(2) Was, at the request of the owner, and following his or her notification of the Department of Housing and Community Development and the assessor, made subject to taxation under this part.

(b)(1) “Manufactured home,” as used in this part, does not include a manufactured home which has become real property by being affixed to land on a permanent foundation system pursuant to Section 18551 of the Health and Safety Code and is taxed as all other real property is taxed.

(2) Except as provided in paragraph (1), a manufactured home, otherwise subject to taxation pursuant to this part, shall not be classified as real property for property taxation purposes that would be excluded from taxation pursuant to this part.