California Code, Government Code - GOV § 12468

(a) For counties with a population in excess of 5,000,000 the audit shall be performed annually.

(b) For counties with a population greater than 200,000 and less than 5,000,000, the audit shall be performed on a three-year cycle.

(c) For counties with a population of 200,000 or less, the audit shall be performed on a five-year cycle.

(d) The Controller may, at the Controller's discretion, perform audits more frequently than provided in subdivisions (b) and (c).

(e) The Controller shall annually submit a report to the Legislature containing a description of the audit findings for each county that was audited during the prior year. The report shall contain recommendations to the Legislature for legislation to correct any errors in the apportionment and allocation of property tax revenues that were determined as a result of these audits.