California Code, Revenue and Taxation Code - RTC § 2308

The maximum property tax rate for a local agency assuming the responsibility for providing a program or service and for levying a tax to pay the cost thereof, as a result of a functional consolidation, shall be the maximum property tax rate for such agency established prior to the functional consolidation plus such additional rate as may be necessary to pay the actual costs of providing such program or service.

The Controller may audit any rate imposed under this section and if he determines that the rate exceeds a rate which would be necessary to pay the actual costs incurred as a result of functional consolidation, he shall immediately notify the local agency of such determination and the local agency shall reduce its property tax rate by an appropriate amount for the next succeeding fiscal year. In the event that a local agency fails to make such a reduction in its property tax rate, the Controller shall request the Attorney General to bring an action under Chapter 2 (commencing with Section 1084) of Title 1 of Part 3 of the Code of Civil Procedure to force a reduction in the rate.