Cal. Revenue and Taxation Code § 38562

If the purchaser of a business fails to withhold from the purchase price as required, the purchaser becomes personally liable for the payment of the amount required to be withheld by him or her to the extent of the purchase price, valued in money. Within 60 days after receiving a written request from the purchaser for a certificate, or within 60 days from the date the former owner’s records are made available for audit, whichever period expires the later, but in any event not later than 90 days after receiving the request, or 90 days from the date of the sale of the business, whichever period expires later, the board shall either issue the certificate or mail notice to the purchaser, at his or her address as it appears on the records of the board, of the amount that must be paid as a condition of issuing the certificate. Failure of the board to mail the notice will release the purchaser from any further obligation to withhold from the purchase price as above provided. The last date upon which the obligation of the successor may be enforced shall be not later than three years after the date the board is notified of the purchase of the business.