The Ontario Building Code | Markings Required
7.7.2.1. Markings Required
(1) Non-potable water piping shall be identified by markings that are permanent, distinct and easily recognized.
(2) Non-potable water system for re-use purposes shall be marked in accordance with Section 12 of CAN/CSA-B128.1, "design and installation of Non-Potable water Systems".
(3) A sign containing the words Non-Potable water, Do Not Drinkshall be in letters at least 25 mm high with a 5 mm stroke and posted immediately above a fixture that is permitted to receive non-potable water.
7.7.3. Location