California Code, Government Code - GOV § 53881

For purposes of this article, a district shall be deemed to have made a reasonable effort to ascertain the names and addresses of each party holding an interest in delinquent property if it obtains a title guarantee, lot book guarantee, or similar guarantee from a title company, or searches the official records of the county in which the delinquent property is located.  The cost of ascertaining the names and addresses of each party, including without limitation, the costs of any guarantees obtained from title companies, shall be added to the amount of the delinquency that shall be paid in order to cure the delinquency or redeem the delinquent property, or both.