Stormwater and all other unpolluted drainage shall be discharged to such sewers as are specifically designed as combined sewers or storm sewers, or to unpolluted process waters which may be discharged, on approval of the city engineer, to a storm sewer, combined sewer, or natural outlet. (Ord. 016/2021 § 2; Ord. 1260, 2002; Ord. 722, 1981)