Cal. Sts. & High. Code § 35471

Immediately upon the recording, the several assessments contained in the assessment roll are due and payable, and each assessment is a lien upon the property against which it is made. Unless sooner discharged, the lien shall continue for four years from the date of recording, or if bonds are issued to represent the assessment, the lien shall continue until the expiration of four years after the due date of the last installment upon the bonds or the last principal coupon attached to them.