Cal. RTC § 4985.5

(a) Notwithstanding Section 2610.5, in the case of cancellations made to the roll pursuant to Section 1646.1, where a taxpayer has failed to pay an amount of tax computed upon assessed value that is the subject of a pending informal review based upon paragraph (2) of subdivision (a) of Section 51, the relief from penalties shall apply only to the difference between the county assessor’s final determination of value and the value on the assessment roll for the fiscal year covered by the application.

(b) This section shall apply only to those properties upon which an application for an informal review based upon paragraph (2) of subdivision (a) of Section 51 is pending before the county assessor on the effective date of the act adding this section or those applications for an informal review based upon paragraph (2) of subdivision (a) of Section 51 that are filed with the county board after the effective date of the act adding this section.

(c) For any taxpayer that has paid at least 80 percent of the amount of tax finally determined due by the county assessor within 30 days of filing an application for reassessment, the tax collector shall accept payment of the balance of the tax due without penalties or interest.

(d) The county tax collector shall notify all taxpayers that receive a tax bill of the provisions of this section.

(e) This section shall only become operative if the board of supervisors of a county, with the approval of the county’s tax collector and the county’s auditor, adopts a resolution or ordinance approving this section.