Cal. Unemployment Insurance Code § 1206

A notice given under this chapter by the director, an administrative law judge, or the appeals board: (a) May be served personally or by mail, except that service by mail given by the director shall be made by certified mail in the following cases: (1) Under Sections 1137 and 1221. (2) Under Sections 1131, 1142, 1143, 1144, 1184, 1733, and 1735 if the assessment is in excess of one thousand dollars ($1,000). (3) Under Section 1180 if the denial of claim for refund or credit is in excess of one thousand dollars ($1,000). (b) If served by mail, the notice shall be: (1) Addressed to the employing unit or person at his or her address as it appears on the records of the department. (2) Complete at the time of deposit in the United States mail. (3) Made pursuant to Section 1013 of the Code of Civil Procedure, excepting service of notice of a hearing before or an order or a decision of an administrative law judge or of the appeals board in transfer of reserve account, reassessment and refund matters. (c) May be served electronically or by a computerized service if service by certified mail is not required and the manner of service is agreed to by the recipient.