Cal. Rev. & Tax. Code § 1605.6
After the filing of an application for reduction of an assessment, the clerk of the county board of equalization shall set the matter for hearing and notify the applicant, or his or her designated representative, of the time and date of the hearing. Notice of the time, date, and place of the hearing shall be given not less than 45 days prior to the hearing, unless the assessor and the applicant, or the applicant's designated representative, stipulate orally or in writing to a shorter notice period. If the hearing on a particular application is vacated for any reason, the clerk of the county board of equalization shall notify the applicant, or the applicant's designated representative, of the new time, date, and place of the hearing not less than 10 days prior to the new hearing date, unless the assessor and the applicant, or the applicant's designated representative, stipulate orally or in writing to a shorter notice period, or the application has been heard by a hearing officer in accordance with Article 1.7 (commencing with Section 1636). At the option of the clerk of the county board of equalization, the notice required by this section may be electronically transmitted, if requested in writing by the taxpayer, to an electronic address designated by the taxpayer. The clerk may also opt to electronically transmit the notice required by this section to the assessor, if requested by the assessor, to an electronic address designated by the assessor.
Ca. Rev. and Tax. Code § 1605.6