Add the strawberries, water, and sugar into a large blender. Blend for 1 to 2 minutes until smooth. You may have to do this in batches if your blender isn't big enough.
Taste and blend in more sugar if desired. Strain the mixture into a pitcher to remove any seeds and pulp.
Serve immediately over ice or chill in the refrigerator for up to 3 days. Garnish with lime wedges and mint sprigs if desired.
Notes
For a less sweet agua fresca, only use half of the sugar.
You can add the juice of one lime for a citrus twist.
Garnish with mint leaves for an even more refreshing flavor.
You can replace the sugar with your preferred sweetener, like honey or agave syrup.