It shall be the duty of the Director of Public Works, in accordance with State regulations, to draw or have drawn specimens of water from at least four (4) points in the water system, such points to be chosen by the Director of Public Works. The water so drawn for specimens shall be submitted to a qualified laboratory approved by the State Department of Public Health for testing as to purity, and report on such tests shall be filed in the Office of Director of Public Works and such other agencies as required by law. (1974 Code § 1-518)