The double check valve or other approved backflow protection devices may be inspected and tested periodically for watertightness by the city. The devices shall be serviced, overhauled, or replaced whenever they are found defective, and all costs of repair and maintenance shall be borne by the customer. [Ord. 910 Art. 7, § 11, 2016; Ord. 878 Art. 7, § 11, 2015.]