California Code, Streets and Highways Code - SHC § 18154

When the city becomes the purchaser the land shall not again be sold for any succeeding delinquent assessment, penalties and interest until it has been redeemed from the previous sale.  The city shall, however, unless a resale has been made by it, from time to time when due transfer into said special fund, pending redemption, the amount of any succeeding delinquent assessment, penalties and interest.  No redemption shall be made until all delinquent assessments, penalties and interest are paid.  The purchaser at any delinquent sale, or at any resale by the city if the city was the purchaser, shall take the land subject to all unpaid assessments, penalties and interest due under this chapter.