ARSD 20:54:25:03. Backflow

The water-distributing system and each water outlet must be protected against backflow. The water outlet must: (1) Have the outlet end from which the water flows spaced a distance above the flood-level rim of the receptacle into which the water flows, which is sufficient to provide a minimum air gap as required in table 603.3.1 of the Uniform Plumbing Code, 2024 edition; or (2) If it is not possible to provide a minimum air gap, be equipped with an accessible backflow preventer installed on the discharge side of the manual control valve, which complies with section 603.2 of the Uniform Plumbing Code, 2024 edition.