Watermelon Agua Fresca

Add watermelon to a blender and blend until completely pureed. Using a fine mesh sieve, pour puree through into a large bowl or measuring cup, using a spoon to press the last of the liquid out when you get to the end. Combine watermelon juice, water, lime juice and sugar in a large pitcher. Taste and add more sugar if needed. You can also stir in some fresh mint leaves (or just garnish the drinks with them) for taste. Chill until cold.