California Code, Revenue and Taxation Code - RTC § 531

If any property belonging on the local roll has escaped assessment, the assessor shall assess the property on discovery at its value on the lien date for the year for which it escaped assessment. It shall be subject to the tax rate in effect in the year of its escape except as provided in Section 2905 of this code.

Property shall be deemed to have escaped assessment when its owner fails to file a property statement pursuant to the provisions of Section 441, to the extent that this failure results in no assessment or an assessment at a valuation lower than would have obtained had the property been properly reported. Escape assessments made as the result of an owner's failure to file a property statement as herein provided shall be subject to the penalty and interest imposed by Sections 463 and 506, respectively. This paragraph shall not constitute a limitation on any other provision of this article.