Cal. Rev. & Tax. Code § 7287.22

(a) Notwithstanding any other law, the County of Contra Costa, by ordinance, may impose a transactions and use tax for general or specific purposes at a rate of no more than 0.625 percent that would, in combination with all taxes imposed pursuant to Part 1.6 (commencing with Section 7251), exceed the limit established in Section 7251.1, if all of the following requirements are met:
1. (1) The board of supervisors of the County of Contra Costa adopts an ordinance proposing the transactions and use tax by any applicable voting approval requirement.
2. (2) The ordinance proposing the transactions and use tax is submitted to the electorate and is approved by the voters voting on the ordinance in accordance with the California Constitution.
3. (3) The transactions and use tax conforms to the Transactions and Use Tax Law (Part 1.6 (commencing with Section 7251)), other than Section 7251.1.
(b) Notwithstanding Section 7251.1, a transactions and use tax rate imposed pursuant to subdivision (a) shall not be considered for purposes of the combined rate limit established by Section 7251.1.
(c) If, as of December 31, 2031, an ordinance proposing a transactions and use tax has not been approved in the County of Contra Costa as authorized by subdivision (a), this chapter shall be repealed.