Cal. Health & Safety Code § 18214

(a) “Mobilehome park” is any area or tract of land where two or more lots are rented or leased, held out for rent or lease, or were formerly held out for rent or lease and later converted to a subdivision, cooperative, condominium, or other form of resident ownership, to accommodate manufactured homes, mobilehomes, or recreational vehicles used for human habitation. The rental paid for a manufactured home, a mobilehome, or a recreational vehicle shall be deemed to include rental for the lot it occupies. This subdivision shall not be construed to authorize the rental of a mobilehome park space for the accommodation of a recreational vehicle in violation of Section 798.22 of the Civil Code.
(b) Notwithstanding subdivision (a), employee housing that has obtained a permit to operate pursuant to the Employee Housing Act (Part 1 (commencing with Section 17000)) and that both meets the criteria of Section 17021.6 and is comprised of two or more lots or units held out for lease or rent or provided as a term or condition of employment shall not be deemed a mobilehome park for the purposes of the requirement to obtain an initial or annual permit to operate or pay any related fees required by this part.
(c) Notwithstanding subdivision (a), an area or tract of land shall not be deemed a mobilehome park if the structures on it consist of residential structures that are rented or leased, or held out for rent or lease, if those residential structures meet both of the following requirements:
1. (1) The residential structures are manufactured homes constructed pursuant to the National Manufactured Housing Construction and Safety Standards Act of 1974 (42 U.S.C. Sec. 5401 et seq.) or mobilehomes containing two or more dwelling units for human habitation.
2. (2) Those manufactured homes or mobilehomes have been approved by a city, county, or city and county pursuant to subdivision (e) of Section 17951 as an alternate which is at least the equivalent to the requirements prescribed in the California Building Standards Code or Part 1.5 (commencing with Section 17910) in performance, safety, and for the protection of life and health.
(d) Notwithstanding subdivision (a), an area or tract of land shall not be deemed a mobilehome park due to the rental or lease of an accessory dwelling unit created by use of a manufactured home, as defined in Section 66313 of the Government Code.