Cal. Pub. Util. Code § 98060

If any special election is held exclusively on the proposition or propositions related to the transit district organization, bond issuance, raising of tax levy, or any other transit district purpose, the expenditures therefor shall be reimbursed to the county by means of a tax on all the taxable property within the district, and this tax shall be added to the next county tax bills by the proper official of the county.