California Code, Health and Safety Code - HSC § 14922

The lien, whether bonds issued to represent the assessment or otherwise, shall be subordinate to all fixed special assessment liens previously imposed upon the same property, but it shall have priority over all fixed special assessment liens which may thereafter be created against the property. The lien of a reassessment and of a refunding assessment shall be the same as the original assessment to which it relates. A supplemental assessment is a new assessment.