California Code, Revenue and Taxation Code - RTC § 2134

Any district levying or causing to be levied a tax in accordance with the provisions of this part may levy or cause to be levied a tax in one or more counties in excess of any maximum tax rate established by law or pursuant to law; provided that the total revenue to be received from the tax levies in all counties does not exceed the total revenue which would have been received by the district by levying the tax at the maximum rate in all counties without complying with the provisions of this part.