Process mango, sugar, and 4 cups of water in a blender on medium for 60 seconds.
Using a mesh strainer, strain mixture into a large pitcher. Discard or compost pulp. Mix in remaining 2 cups of water.
Chill and serve over plenty of ice when you're ready to enjoy this refreshing agua fresca.
A Note from Lola
ON SWEETENERS
I prefer my aguas frescas to be only slightly sweetened, so feel free to adjust the level of sweetness to your liking or skip the sugar altogether. If you want it on the sweet side, the way most aguas frescas are served in Mexico, use 1/2 cup of sugar in this recipe.
My preferred natural sweeteners include pure cane sugar, simple syrup, agave, or dates.
I love how in many parts of Oaxaca, vendors now make aguas frescas with no sweeteners and have a pitcher of simple syrup to add it when requested.