Cal. Public Utilities Code § 132307

(a) The commission, subject to the approval of the voters within the portion of the county to which the tax would apply, may impose a maximum tax rate of 1 percent under this chapter and the Transactions and Use Tax Law (Part 1.6 (commencing with Section 7251) of Division 2 of the Revenue and Taxation Code), and the commission may state the maximum tax rate in terms of not to exceed 1 percent, or any lesser percentage thereof. The commission shall not levy the tax at a rate other than 1 percent or three-fourths, one-half, or one-fourth of 1 percent, unless specifically authorized by the Legislature. (b) The tax rate adopted pursuant to this article, unless otherwise prohibited, may be increased by the commission by ordinance adopted in the manner and by the vote stated in Section 132301 and approved by a majority of the electors voting on the measure at an election called for that purpose by the commission.