Cal. Rev. & Tax. Code § 2612

On the tax bill for tax-defaulted property shall appear in writing the fact that prior year taxes are in default. The tax bill may contain language such as “prior year taxes delinquent,” “prior year taxes in default,” “unpaid prior year taxes jeopardize property,” or any other language which would indicate the fact that the property is in jeopardy as a result of delinquent prior year taxes.