Cal. Sts. & Hy. Code § 27323
If the district has not incurred a bonded indebtedness at the time of the application by the board of supervisors to join the district, the county or part thereof may be annexed if the board of supervisors passes an ordinance declaring its intention to join the district and upon petition presented in the manner provided in this part for the organization of the district. The petition shall be presented to the Secretary of State, who shall give notice of the presentation thereof, and of the date set for receiving protests against the annexation in the same manner as for original petitions, and all of the provisions of this part which are applicable to original petitions shall be applicable to petitions for annexations.
Ca. Sts. and High. Code § 27323