Cal. Rev. & Tax. Code § 2206
"Costs mandated by the federal government" means any increased costs mandated specifically by the federal government upon a local agency or school district after January 1, 1973, in order to comply with requirements of federal statute or regulation. "Costs mandated by the federal government" includes costs resulting from enactment of a state law or regulation where failure to enact such law or regulation to meet specific federal program or service requirements would result in substantial monetary penalties or loss of funds to public or private persons in the state. "Costs mandated by the federal government" does not include costs which are specifically reimbursed or funded by the federal or state government or programs or services which may be implemented at the option of the state, local agency, or school district.
Ca. Rev. and Tax. Code § 2206