
Prepare the syrup: Combine a cup (236ml) of the water and the sugar in a small saucepan over medium-low heat. Stir frequently until sugar is dissolved. Remove from heat and set aside to cool for at least 10 minutes.
Pour lemon juice into a large pitcher. Add cooled simple syrup and cranberry juice.
Add remaining 5 cups (1.2L) water and stir well.
Cover and store in the refrigerator to chill before serving or serve immediately poured over ice. Always stir before pouring.