Cal. Rev. & Tax. Code § 746

Each year, upon or prior to the completion of the assessment roll prepared by the board, but not later than June 15, the board shall mail notice to each assessee at its address as shown on the records of the board, of the allocated assessed values of the assessee’s unitary property that have been or are proposed to be placed on the assessment roll to be transmitted to county auditors. The notice shall advise the assessee that a petition for a correction of an allocated assessment may be filed, not later than July 20 of the year of the notice, at the headquarters of the board in Sacramento.