California Code, Revenue and Taxation Code - RTC § 2271.1

An additional property tax heretofore or hereafter levied pursuant to the provisions of Section 2271 shall not be invalidated and may continue to be levied to meet recurring costs resulting from any program or activity undertaken or implemented by a local agency in order to comply with a mandate by the federal government, by initiative enactment or the courts, notwithstanding the reversal, repeal, stay, or invalidation of such mandate, if the reversal, repeal, stay, or invalidation of the mandate occurred or occurs after the local agency has made such additional levy to satisfy continuing contractual obligations entered into in order to undertake, implement or continue the mandated program or activity.

The additional rate shall not continue to be levied if the reversal, repeal, stay, or invalidation of the mandate is upheld by a final court order.