California Code, Government Code - GOV § 25202

The board shall equalize assessments and levy taxes upon the taxable property of the county for all county purposes, and also upon the taxable property of any district for the construction and repair of roads and highways and other district purposes.  No tax shall be levied upon any district until the proposition to levy the tax has been submitted to the qualified electors of the district and received a majority of all the votes cast upon the proposition.