California Code, Government Code - GOV § 17615.6

If a local agency or school district realizes a decrease in the amount of costs incurred because a mandate is discontinued, or made permissive, the Controller shall determine the amount of the entitlement attributable to that mandate by determining the base year amount for that mandate for the local agency or school district plus the annual adjustments.  This amount shall be subtracted from the annual subvention which would otherwise have been allocated to the local agency or school district.