A retail transactions and use tax ordinance may be adopted by the board in accordance with the provisions of Part 1.6 (commencing with Section 7251) of Division 2 of the Revenue and Taxation Code, provided that two-thirds of the electors voting on the measure vote to authorize its enactment at a special election called for that purpose by the board.
Source:
Section 100250, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=PUC§ionNum=100250..