California Code, Revenue and Taxation Code - RTC § 3692

(a) The tax collector shall attempt to sell tax-defaulted property, as provided in this chapter, within four years of the time that the property becomes subject to sale for nonpayment of taxes unless, by other provisions of law, the property is not subject to sale. If there are no acceptable bids at the attempted sale, the tax collector shall attempt to sell the property at intervals of no more than six years until the property is sold.

(b) When oil, gas, or mineral rights are subject to sale for nonpayment of taxes, the tax collector may offer the interest at minimum bid to the holders of outstanding interests where the interest subject to sale is a partial interest or, where the interest subject to sale is a complete and undivided interest, to the owner or owners of the property to which the oil, gas, or mineral rights are appurtenant.

(c) When parcels that are rendered unusable by their size, location, or other conditions are subject to sale for nonpayment of taxes, the tax collector may offer the parcel, at a minimum bid, to owners of contiguous parcels or to a holder of record of either a predominant easement or a right-of-way easement. If the parcel is sold to a contiguous property owner, the tax collector shall require that the successful bidder request the assessor and the planning director to combine the unusable parcel with the bidder's own parcel as a condition of sale.

(d) Sealed bid sale procedures shall be used when offers are made pursuant to subdivision (b) or subdivision (c), and the property shall be sold to the highest eligible bidder. The offers shall remain in effect for 30 days or until notice is given pursuant to Section 3702, whichever is later.If the highest bidder does not consummate the sale within the time period determined by the tax collector, the tax collector may offer the property to the next highest bidder at their bid price.

(e) The Notice to the Board of Supervisors and Notice of Intended Sale of Tax-Defaulted Property shall indicate that any parcel remaining unsold may be reoffered within a 90-day period and any new parties of interest shall be notified in accordance with Section 3701. This subdivision does not apply to properties sold pursuant to Chapter 8 (commencing with Section 3771).