California Code, Government Code - GOV § 25694

Any tax for the purposes of this article may be levied only if a proposal therefor, specifying the purpose, the rate of tax, and the number of years for which the tax is to be levied, is submitted to the qualified electors of the county, at a general or special election, and is approved by a majority of the electors voting thereon.  No such tax may be levied if it operates to increase the maximum rate of taxation otherwise prescribed for the county unless the proposal therefor is approved by two-thirds of the electors voting thereon.

Any such proposal for a tax levy shall be submitted to the electors of the county, and the election thereon held, in conformity, as nearly as may be practicable, with the provisions of law applicable to the submission to the electors of a proposition for the issuance of bonds of the county and the conduct of an election thereon.