California Code, Government Code - GOV § 29302

If by law a tax is required or permitted to be levied at one uniform rate on all the taxable property in the county for the purpose of creating, replenishing, or contributing to a fund for particular and specified purposes, the board of supervisors may add the tax rate for such fund to the general fund tax rate for the purpose of simplifying the accounting, and the expenditures authorized to be paid from the special fund may be paid from the general fund by appropriations therefrom. The total appropriated from the general fund for the expenditures authorized to be paid from the special fund shall not exceed the total which would have been received if the special tax had been levied and collected separately.

Any money from sources other than taxation required by law to be deposited in the special fund shall be deposited in the general fund and appropriated for the purposes for which expenditures are required to be made from the particular fund. Any appropriation made from the general fund instead of from a special fund shall not be less than the amount required to be provided in the special fund and shall be used only for the particular purposes for which the special fund is required to be used.