Ill. Admin. Code tit. 77, § 890.1110
All premises intended for human habitation or occupancy shall be provided with a potable water supply. The potable water supply shall not be connected to non-potable water and shall be protected from backflow and back siphonage. (See Appendix I.Illustration A.)
(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)