It shall be the duty of the customer at any premises where backflow prevention devices are installed to contact the Town's certified tester/inspector to have certified inspections and operational tests made at least once a year. In those instances where the Town Board deems the hazard to be great enough, it may require certified inspections at more frequent intervals. Certified inspections and operational tests must also be made when any backflow prevention device is to be installed, repaired, overhauled or replaced, in addition to the requirement of an annual certified inspection and operational test. All inspections and tests shall be at the expense of the customer and shall be performed by the Town's certified tester/inspector or any other qualified firm or persons approved of in advance by the Town. These devices shall be repaired, overhauled or replaced by and at the expense of the customer whenever said devices are found to be defective. Records of such tests, repairs and overhauls shall be maintained. Copies of all testing and maintenance records shall be sent to the Town immediately after the work is performed.