Cal. RTC § 4222

If all payments are not made on or before the dates prescribed, the property may become subject to a power of sale pursuant to Section 3691 in the same manner as if no election to pay delinquent taxes in installments had been made. In the event that the default occurs at the time the second or subsequent installment is due and the assessee or agent of the assessee can, by substantial evidence, convince the tax collector that the payment was not made through any fault of the assessee, the tax collector may reinstate the account upon receipt of a payment in an amount reflecting the installment due plus interest under Section 4221 to the date of reinstatement, provided the payment is physically received by the tax collector prior to the time the property becomes subject to the tax collector’s power to sell or prior to June 30 of the current fiscal year, whichever occurs earlier.