It shall be the duty of the director at any premises where backflow prevention assemblies are installed to have a certified inspection and operational test made at least once per year. In those instances where the director deems the hazard to be great enough, he may require certified testing and inspections at more frequent intervals. These inspections and tests may be at the expense of the water user and shall be performed by the city's water service department's certified personnel, or by a certified tester approved by the director. It shall be the duty of the director to see that these timely tests are made. The customer user shall be notified by the director in advance when the tests are to be undertaken so that he or his representative may witness the tests if it is so desired. Those devices found to be defective shall be repaired, overhauled, or replaced at the expense of the customer user. Records of such tests, repairs, and overhaul shall be kept by the public works department. (Ord. 2009-02, 7-28-2009)