Cal. Unemp. Ins. Code § 2736

The Director of Employment Development shall determine the amount of the overpayment and shall notify the recipient of the basis of the overpayment determination. In the absence of fraud, misrepresentation or willful nondisclosure, notice of the overpayment determination shall be served on the recipient within two years after the beginning of the disability benefit period for which the overpayment was made.