California Streets and Highways Code
Any county or any portion thereof may be added to the district at any time, in accordance with the provisions of this chapter by resolution of the board upon request of the board of supervisors of the county by an ordinance applying for permission for the county or portion thereof to become a part of the district.
If the annexation of any county or portion thereof is proposed to any district already organized the board shall prescribe the terms upon which the territory proposed to be annexed shall be admitted, including the payment of a just proportion of the organization and preliminary expenses originally incurred by the district. No county or portion thereof shall be annexed without first complying with those terms.
If the board consents to the annexation after any bonded debt of this district has been authorized, the board of supervisors so applying for annexation shall call an election at which the proposition to join the district and assume the obligation of the bonds of the district along with the territory already included therein, shall be submitted to the electors of the county or portion thereof as one proposition. Unless the proposition receives two-thirds of the votes cast at the election the county or part thereof shall not be annexed to the district. If the proposition carries by two-thirds or more of the votes cast at the election the result of the election shall be certified to the Secretary of State by the county elections official and thereupon the Secretary of State shall give notice and call for protests in the same manner as upon the original incorporation of the district.
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.
After all protests have been disposed of in the same manner as protests upon the incorporation of the district, the Secretary of State shall issue his certificate certifying to the annexation and describing the boundaries of the district as finally determined, which certificate shall be recorded in the office of the county recorder of each county wherein any portion of the annexed territory is located, and thereupon the boards of supervisors of the county shall appoint a member or members of the board to serve until the expiration of the term of the directors then holding for the term of office that will soonest expire.
Upon the issuance of the certificate of annexation by the Secretary of State the territory named therein shall become a part of the district.