The Ontario Building Code | Plumbing and Drainage Systems
3.7.4.1. Plumbing and drainage Systems
(1) Except as permitted in Sentence (3), each buildingsituated on property that abuts on a street in which a public or municipal water main is located shall be provided with or have accessible to its occupants a plumbing systemincluding a potable water supply, a sanitary drainage system and plumbing fixtures.
(2) When the installation of a sanitary drainage system is not possible because of the absence of a water supply, sanitary privies, chemical closets or other means for the disposal of human waste shall be provided.
(3) Plumbing fixtures need not be provided in a buildingthat is not normally occupied by persons where such installations are impractical and other fixtures are available in nearby buildings when the subject building is in use.