Pub. Util. Code, § 240301

The commission may levy a retail transactions and use tax applicable in the incorporated and unincorporated territory of the county in accordance with this chapter and Part 1.6 (commencing with Section 7251) of Division 2 of the Revenue and Taxation Code. The ordinance shall only become effective if adopted by a two-thirds vote of the commission and subsequently approved by two-thirds of the electors voting on the measure at a special election called for the purpose by the board of supervisors or at any regular election. The commission shall specify in the ordinance that not more than 1 percent of the annual net amount of revenues raised by the tax may be used to fund the salaries and benefits of the staff of the commission in administering the programs funded from that tax. The ordinance shall take effect at the close of the polls on the day of election at which the proposition is adopted. The initial collection of the transactions and use tax shall take place in accordance with Section 240304.

If the voters do not approve the ordinance, the board of supervisors may, at any time thereafter, submit the same, or a different, measure, if adopted by a two-thirds vote of the commission, to the voters in accordance with this division.