Cal. Health & Saf. Code § 4711
The district as formed may include unincorporated or incorporated territory, or both. The incorporated territory included in the district may include the whole or part of one or more cities. However, less than the whole of a city shall not be included in the district except by the vote of a majority of the governing body of the city.
The district shall not include the whole or any part of another sanitation district or any other district formed for similar purposes unless the governing body of such other district shall consent thereto and the board of supervisors, after a hearing, shall find and determine by resolution duly adopted that the proposed inclusion of the whole or part of such other district within the district is in the public interest and the territory affected will benefit thereby.
Notice of such hearing shall be given by publication in at least two successive issues, not more than 30 nor less than 10 days prior to the hearing, in a newspaper of general circulation published within the county.
Ca. Health and Saf. Code § 4711