Cal. Rev. & Tax. Code § 830
(c) Except as hereinafter provided, if any person fails to file the property statement, in whole or in part, by March 1, or by that later date to which the filing period is extended pursuant to subdivision (b) or Section 830.1, a penalty shall be added to the full value of the assessment of so much of the property as is not timely reported as follows:
(d) Any person who subscribes to the board’s tax rate area change service and who receives a change mailed between April 1 and May 1, shall file a corrected statement no later than May 30 with respect to those parts of the property statement that are affected by the change.
If that person receives a change mailed after May 1, a corrected statement shall be filed no later than the 60th day following the mailing of that change.