In a saucepan, heat 250 ml (1 cup) water with the sugar and zest, stirring constantly until the sugar dissolves. Strain and transfer to a pitcher. Add the remaining water and the juice. Stir. Refrigerate until chilled, about 2 hours.
Stir again and serve well chilled.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.