California Code, Civil Code - CIV § 798.33

(a) No lease agreement entered into, modified, or renewed on or after January 1, 2001, shall prohibit a homeowner from keeping at least one pet within the park, subject to reasonable rules and regulations of the park.  This section may not be construed to affect any other rights provided by law to a homeowner to keep a pet within the park.

(b) A homeowner shall not be charged a fee for keeping a pet in the park unless the management actually provides special facilities or services for pets.  If special pet facilities are maintained by the management, the fee charged shall reasonably relate to the cost of maintenance of the facilities or services and the number of pets kept in the park.

(c) For purposes of this section, “pet” means any domesticated bird, cat, dog, aquatic animal kept within an aquarium, or other animal as agreed to between the management and the homeowner.