
Combine the sugar, water, blueberries, and 1 teaspoon lemon zest in a medium pot.
Bring to a boil over medium heat, then simmer for 10 minutes or until the sugar is melted and blueberries are starting to burst.
Remove from heat and pass through a fine sieve. Let this blueberry syrup completely cool.
Meanwhile, juice the lemons to get 1 cup lemon juice.
In a large pitcher, add the blueberry syrup, lemon juice, and ice. Stir together.
Stir in the sparkling water right before enjoying (don’t add to anything you plan on having leftover). Enjoy immediately.