Cal. Wat. Code § 26275
If property sold for delinquent assessments has not been redeemed and five years have elapsed from the date of its sale, at least 30 days prior to the end of the redemption period the collector shall mail a notice specifying the date of sale and advising that, unless redeemed, a collector's deed will be issued to the property at any time after five years from the date of sale has elapsed. The notice shall be sent by certified mail to the last assessee of the property addressed to his last address shown on the assessment roll. Five years after the date of sale, and 30 days after mailing of the notice, the collector, upon demand, shall deliver a collector's deed to the property to the district or to the assignee holding the certificate of sale.
Ca. Water Code § 26275