Cal. Public Utilities Code § 130410

(a) The commission is authorized to impose a maximum tax rate of 1 percent under this article and 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 34, 12, or 14 of 1 percent, unless specifically authorized by the Legislature. (b) The commission, in the ordinance, shall provide for limitations upon the time when the tax shall be in effect. Any tax rate or maximum tax rate adopted pursuant to this article, unless otherwise prohibited, may be increased when authorized by the commission by ordinance adopted in the manner and by the vote stated in Section 130401 and approved by a majority of the electors voting on the measure at an election called for that purpose by the commission.