Cal. RTC § 2273.2

If, prior to January 1, 1973, a local agency was a party to any contract or lease, the terms of which provide (1) that the local agency shall make payments to the federal government, the State of California or any other local agency and (2) that the governing body of such local agency shall, whenever necessary, levy an ad valorem property tax sufficient to provide for all payments under the contract or lease in a timely manner, such local agency may levy, or have levied on its behalf, a rate in addition to the maximum property tax rate established pursuant to this chapter (commencing with Section 2201) for the purpose of making such payments as are required by such contract or lease; provided, that, the provisions of this section shall apply to a contract or lease signed after January 1, 1973, which contains the terms stated in (1) and (2) above if the terms of such contract or lease are designed to prevent an increase in the burden on the taxpayers of the local agency by means of providing for a reduction in payments under a contract or lease signed before January 1, 1973, to which this section is applicable, in amounts at least equal to the payments required under the contract or lease signed after January 1, 1973.