California Code, Government Code - GOV § 53739

(b)(1) Except as provided in paragraph (2), an ordinance or resolution presented for voter approval pursuant to Article XIII C or XIII D of the California Constitution may provide that the tax, assessment, or property-related fee or charge rates or amounts stated in that ordinance or resolution may be adjusted for inflation pursuant to a clearly identified formula stated in that ordinance or resolution. If an ordinance or resolution described in the preceding sentence is approved by the requisite number of votes at an election held for that purpose, the governing board of the adopting local government may thereafter impose the tax, assessment, or property-related fee or charge at any rate or amount that is less than or equal to the inflation-adjusted maximum amount authorized by the voter-approved ordinance or resolution.

(2) Notwithstanding the authority established in paragraph (1), if the amount or rate of a tax, assessment, or property-related fee or charge is determined by using a percentage calculation, the ordinance imposing the tax, assessment, or property-related fee or charge may not provide that the percentage will be adjusted for inflation.