California Code, Streets and Highways Code - SHC § 6572

If any sale of lands for delinquency in the payment of principal or interest of any bond is held illegal or invalid, or any deed issued to the purchaser at any such sale is held illegal or invalid for any reason whatsoever, the lands described in the bond shall not be released from the lien of the assessment but shall be and remain subject to further proceedings for the enforcement of the assessment, and the further proceedings may include additional sales or the issuance of new deeds. In any event, however, the lien of the assessment shall continue only until a valid sale is had and a valid deed issued, or until the expiration of two years after such sale or deed is held illegal or invalid, whichever is sooner.