(a) No person shall discharge or cause to be discharged any storm water, surface water, ground water, roof runoff, subsurface drainage, uncontaminated cooling water or unpolluted industrial process waters to any sanitary sewer.
(b) Storm water and all other unpolluted drainage shall be discharged to such sewers as are specifically designated as storm sewers or to a natural outlet approved by the director of public works. Industrial cooling water or unpolluted process waters may be discharged on approval of the director of public works, to a storm sewer or natural outlet.