California Code, Government Code - GOV § 66494

(a) If the taxes or special assessments are allowed to become delinquent, the county shall recover from the security the principal sum of the security without proof of loss.  The county shall apply the sum received in payment of any or all of such taxes or special assessments, including penalties and costs, if any, accruing thereto, to the proper state, county, municipal or district officers, for the satisfaction of the tax and special assessment liens and shall pay the balance, if any, over to the surety or depositor.

(b) If the taxes or special assessments are allowed to become delinquent and the security consists of a deposit of money, negotiable bond or instrument of credit, the clerk, subject to any rules of the board of supervisors with respect thereto, shall apply the proceeds thereof to the payment of such taxes and special assessments, including penalties and costs.  Any excess proceeds shall be deposited in the county treasury for the benefit of the persons entitled thereto.

(c) If authorized by prior agreement with the subdivider or his or her sureties, when secured taxes become due the amount of taxes and special assessments may be paid to the county tax collector from the security deposit, or the negotiable paper or instrument of credit may be cashed and any excess proceeds placed in the county treasury subject to refund claim by the subdivider.