Cal. Sts. & High. Code § 8778

If a deficiency remains in the redemption fund after one year from the issuance of the bonds, the legislative body may require all persons interested to appear before it at a day, hour and place fixed by it for a hearing and to show cause why a supplemental assessment should not be made to pay for the cost and incidental expenses of the original work done upon which the original assessments were made upon which the bonds were issued.