The deposits or bonds mentioned in Section 13.12.140 may be refunded or the bonds exonerated not less than twelve months after acceptance of the completion of the excavation work, unless there is written certification by the public works director that the work was not done and completed satisfactorily, and in the manner required by this chapter. In such event, the city shall have the right to require the surety on such bond to complete such work and charge the cost thereof against the bond, or the city may perform said work itself, charge the same against the deposit or bond, and hold the applicant depositing the same liable for any deficiency between the cost of the work and the amount of the deposit or bond. (Ord. 1970 NCS §3 (part), 1994; Ord. 1369 NCS §2 (part), 1979.)