Cal. VEH § 13106

(a) When the privilege of a person to operate a motor vehicle is suspended or revoked, the department shall notify the person by first-class mail of the action taken and of the effective date of that suspension or revocation, except for those persons personally given notice by the department, a court, a peace officer pursuant to Section 13388 or 13382, or otherwise pursuant to this code. It shall be a rebuttable presumption, affecting the burden of proof, that a person has knowledge of the suspension or revocation if notice has been sent by first-class mail by the department pursuant to this section to the most recent address reported to the department pursuant to Section 12800 or 14600, or any more recent address on file if reported by the person, a court, or a law enforcement agency, or to the most recent electronic delivery address provided in accordance with Section 1801.2, and the notice has not been returned to the department as undeliverable or unclaimed. It is the responsibility of a holder of a driver’s license to report changes of address to the department pursuant to Section 14600.

(b) The department may utilize alternative methods for determining the whereabouts of a driver whose driving privilege has been suspended or revoked pursuant to this code for the purpose of providing the driver with notice of suspension or revocation. Alternative methods may include, but are not limited to, cooperating with other state agencies that maintain more current address information than the department’s driver’s license files.