California Code, Streets and Highways Code - SHC § 27322

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.