Cal. Rev. & Tax. Code § 4219

Election to pay delinquent taxes in installments is made by payment, in the same manner as a redemption, of 20 percent, or more, of the redemption amount. All current taxes, with penalties thereon, due or coming due in the fiscal year in which this first payment is made shall be paid before the delinquency date of the last installment of current taxes, except that if the election to pay delinquent taxes in installments is made on or after the delinquency date of the last installment of current taxes in any fiscal year, the current taxes, with penalties and costs thereon, shall be paid with or prior to the installment payment.