Cal. HSC § 4614.5

Whenever the governing body of each city which is included in whole or in part within the district which is to be organized, and the board of supervisors if the district includes any unincorporated territory, has consented to the formation of the district by filing a resolution of concurrence with the governing body of the initiating city, the governing body of the initiating city has full jurisdiction to proceed with the formation of the proposed district. Upon the filing with the governing body of the initiating city of all necessary concurring resolutions of the governing body of any city or of the board of supervisors of the county, as the case may be, the governing body of the initiating city has the sole and exclusive jurisdiction to proceed with the formation of the district, to conduct all hearings on the formation of the district, to make all necessary changes in the boundaries of the proposed district or improvement, to conduct all proceedings on the formation of the district and to take any other action permitted by this chapter with like force and effect as though such district were wholly within the boundaries of the initiating city. The governing body of the initiating city shall not, however, add to the district at the hearing which is provided for by Section 4611 any territory within another city or within unincorporated territory unless it first obtains a consent to such addition which is expressed by a resolution adopted by the governing body of such other city or by the board of supervisors, as the case may be.