Cal. Gov. Code § 53867

If by resolution adopted by a four-fifths vote the legislative body determines that the property cannot be sold for a sum of money at least equal to the total of the amount paid, all accrued penalties and delinquencies, and necessary expenses incurred, the local agency may sell the property or lien for less than such total but not less than the fair market value of the property or lien as determined by the legislative body.