California Code, Civil Code - CIV § 798.22

(a) In any new mobilehome park that is developed after January 1, 1982, mobilehome spaces shall not be rented for the accommodation of recreational vehicles as defined by Section 799.29 unless the mobilehome park has a specifically designated area within the park for recreational vehicles, which is separate and apart from the area designated for mobilehomes.  Recreational vehicles may be located only in the specifically designated area.

(b) Any new mobilehome park that is developed after January 1, 1982, is not subject to the provisions of this section until 75 percent of the spaces have been rented for the first time.