California Code, Water Code - WAT § 51600

(a) After any installment of an unpaid assessment on which bonds have not been issued has become delinquent, the county treasurer may, only upon the request of the district, publish once a week for two weeks in a newspaper of general circulation published in each county where delinquency exists a notice containing a list of all delinquencies in the county.  At the same time as the publication, the county treasurer shall mail the notice to the last known address of the property owner, as shown on the latest county tax roll.

(b) No property may be sold pursuant to this article in the absence of publication and notice to the owner pursuant to subdivision (a).