An approved backwater valve shall be installed in the building sewer of any newly constructed, or remodeled nonresidential and multifamily residential building and in any newly constructed single-family residential building in an accessible location. An approved clean-out must be included and located between the backwater valve and the sewer main. The director is authorized to adopt regulations on approved backwater valves, clean-outs, location and installation. (Ord. 2031 § 2, 1995; Ord. 1706 § 14.90.910, 1989; Ord. 147 § 6.04, 1963)