California Code, Public Utilities Code - PUC § 29123

The tax rate for taxes levied in any fiscal year for all district purposes other than taxes levied pursuant to Section 29121, shall not exceed five cents ($0.05) on each one hundred dollars ($100) of assessed valuation of taxable property within the district, except the tax rate for the first year of levy may include an additional amount sufficient to repay temporary borrowing incurred pursuant to Article 5 of Chapter 8 of this part.  Taxes levied pursuant to this section for maintenance and operation of rapid transit facilities shall be supplementary to the revenues derived from such facilities and shall be limited to actual requirements.